diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/citydlg_common.c freeciv-patched/client/citydlg_common.c
--- freeciv-cvs/client/citydlg_common.c	2003-07-10 11:53:34.000000000 +0100
+++ freeciv-patched/client/citydlg_common.c	2003-07-24 17:05:30.000000000 +0100
@@ -136,9 +136,9 @@
   stock = pcity->shield_stock;
 
   if (pcity->is_building_unit) {
-    cost = get_unit_type(pcity->currently_building)->build_cost;
+    cost = unit_value_adjusted(pcity->currently_building, pcity);
   } else {
-    cost = get_improvement_type(pcity->currently_building)->build_cost;
+    cost = improvement_value_adjusted(pcity->currently_building, pcity);
   }
 
   if (!pcity->is_building_unit && pcity->currently_building == B_CAPITAL) {
@@ -192,10 +192,10 @@
 
     if (is_unit) {
       name = get_unit_name(id);
-      cost = get_unit_type(id)->build_cost;
+      cost = unit_value_adjusted(id, pcity);
     } else {
       name = get_impr_name_ex(pcity, id);
-      cost = get_improvement_type(id)->build_cost;
+      cost = improvement_value_adjusted(id, pcity);
     }
 
     if (turns < 999) {
@@ -231,7 +231,7 @@
       my_snprintf(buf[1], column_size, "%d/%d/%d", ptype->attack_strength,
 		  ptype->defense_strength, ptype->move_rate / 3);
     }
-    my_snprintf(buf[2], column_size, "%d", ptype->build_cost);
+    my_snprintf(buf[2], column_size, "%d", unit_value_adjusted(id, pcity));
   } else {
     /* Total & turns left meaningless on capitalization */
     if (id == B_CAPITAL) {
@@ -260,7 +260,7 @@
       }
 
       my_snprintf(buf[2], column_size, "%d",
-		  get_improvement_type(id)->build_cost);
+		  improvement_value_adjusted(id, pcity));
     }
   }
 
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/cityrepdata.c freeciv-patched/client/cityrepdata.c
--- freeciv-cvs/client/cityrepdata.c	2003-07-10 11:53:34.000000000 +0100
+++ freeciv-patched/client/cityrepdata.c	2003-07-24 17:05:30.000000000 +0100
@@ -374,10 +374,10 @@
 
     if(pcity->is_building_unit) {
       name = get_unit_type(pcity->currently_building)->name;
-      cost = get_unit_type(pcity->currently_building)->build_cost;
+      cost = unit_value_adjusted(pcity->currently_building, pcity);
     } else {
       name = get_impr_name_ex(pcity, pcity->currently_building);
-      cost = get_improvement_type(pcity->currently_building)->build_cost;
+      cost = improvement_value_adjusted(pcity->currently_building, pcity);
     }
 
     my_snprintf(buf, sizeof(buf), "%s (%d/%d/%s/%d)%s", name,
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/climisc.c freeciv-patched/client/climisc.c
--- freeciv-cvs/client/climisc.c	2003-07-24 17:04:38.000000000 +0100
+++ freeciv-patched/client/climisc.c	2003-07-24 17:05:30.000000000 +0100
@@ -624,7 +624,7 @@
 
     if (is_unit) {
       name = get_unit_name(id);
-      cost = get_unit_type(id)->build_cost;
+      cost = unit_value_adjusted(id, pcity);
       pitem->section = unit_type_flag(id, F_NONMIL) ? 2 : 3;
     } else {
       name = get_impr_name_ex(pcity, id);
@@ -632,7 +632,7 @@
 	cost = -1;
 	pitem->section = 1;
       } else {
-	cost = get_improvement_type(id)->build_cost;
+	cost = improvement_value_adjusted(id, pcity);
 	if (is_wonder(id)) {
       	  pitem->section = 4;
         } else {
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/gui-gtk/citydlg.c freeciv-patched/client/gui-gtk/citydlg.c
--- freeciv-cvs/client/gui-gtk/citydlg.c	2003-07-24 17:01:32.000000000 +0100
+++ freeciv-patched/client/gui-gtk/citydlg.c	2003-07-24 17:05:30.000000000 +0100
@@ -1901,7 +1901,7 @@
   get_city_dialog_production(pcity, buf, sizeof(buf));
 
   if (pcity->is_building_unit) {
-    cost = get_unit_type(pcity->currently_building)->build_cost;
+    cost = unit_value_adjusted(pcity->currently_building, pcity);
     descr = get_unit_type(pcity->currently_building)->name;
   } else {
     if (pcity->currently_building == B_CAPITAL) {
@@ -1909,7 +1909,7 @@
       gtk_widget_set_sensitive(pdialog->overview.buy_command, FALSE);
       cost = 0;
     } else {
-      cost = get_improvement_type(pcity->currently_building)->build_cost;;
+      cost = improvement_value_adjusted(pcity->currently_building, pcity);
     }
     descr = get_impr_name_ex(pcity, pcity->currently_building);
   }
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/client/gui-gtk-2.0/citydlg.c freeciv-patched/client/gui-gtk-2.0/citydlg.c
--- freeciv-cvs/client/gui-gtk-2.0/citydlg.c	2003-07-24 17:01:32.000000000 +0100
+++ freeciv-patched/client/gui-gtk-2.0/citydlg.c	2003-07-24 17:05:30.000000000 +0100
@@ -1505,7 +1505,7 @@
   get_city_dialog_production(pcity, buf, sizeof(buf));
 
   if (pcity->is_building_unit) {
-    cost = get_unit_type(pcity->currently_building)->build_cost;
+    cost = unit_value_adjusted(pcity->currently_building, pcity);
     descr = get_unit_type(pcity->currently_building)->name;
   } else {
     if (pcity->currently_building == B_CAPITAL) {
@@ -1513,7 +1513,7 @@
       gtk_widget_set_sensitive(pdialog->overview.buy_command, FALSE);
       cost = 0;
     } else {
-      cost = get_improvement_type(pcity->currently_building)->build_cost;;
+      cost = improvement_value_adjusted(pcity->currently_building, pcity);
     }
     descr = get_impr_name_ex(pcity, pcity->currently_building);
   }
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/city.c freeciv-patched/common/city.c
--- freeciv-cvs/common/city.c	2003-07-24 17:05:30.000000000 +0100
+++ freeciv-patched/common/city.c	2003-07-24 17:05:30.000000000 +0100
@@ -283,12 +283,12 @@
   int build=pcity->shield_stock;
 
   if (pcity->is_building_unit) {
-    total=unit_value(pcity->currently_building);
+    total = unit_value_adjusted(pcity->currently_building, pcity);
     if (build>=total)
       return 0;
     cost=(total-build)*2+(total-build)*(total-build)/20; 
   } else {
-    total=improvement_value(pcity->currently_building);
+    total = improvement_value_adjusted(pcity->currently_building, pcity);
     if (build>=total)
       return 0;
     cost=(total-build)*2;
@@ -1380,8 +1380,13 @@
   int city_shield_surplus = pcity->shield_surplus;
   int city_shield_stock = include_shield_stock ?
       city_change_production_penalty(pcity, id, id_is_unit, FALSE) : 0;
-  int improvement_cost = id_is_unit ?
-    get_unit_type(id)->build_cost : get_improvement_type(id)->build_cost;
+  int improvement_cost;
+
+  if (id_is_unit) {
+    improvement_cost = unit_value_adjusted(id, pcity);
+  } else {
+    improvement_cost = improvement_value_adjusted(id, pcity);
+  }
 
   if (include_shield_stock && (city_shield_stock >= improvement_cost)) {
     return 1;
@@ -1855,6 +1860,10 @@
   int attackpct[UCL_LAST + 1];                /* Attack multipliers */
   int defensefppct[UCL_LAST + 1];             /* Firepower multipliers */
   int attackfppct[UCL_LAST + 1];
+  int impr_cost_adj;			      /* Cost modifiers */
+  int unit_cost_adj[UCL_LAST + 1];
+  int impr_cost_pct;			      /* Cost multipliers */
+  int unit_cost_pct[UCL_LAST + 1];
   int makecontentpct = 100, forcecontentpct = 100;
   int makecontentmil = 0, makecontentmilper = 0;
   int corruptadj = 0, corruptpct = 100;
@@ -1874,8 +1883,10 @@
   pplayer = city_owner(pcity);
   gov = get_gov_pcity(pcity);
 
+  impr_cost_pct = impr_cost_adj = 100;
   for (i = 0; i <= UCL_LAST; i++) {
     defensepct[i] = attackpct[i] = defensefppct[i] = attackfppct[i] = 100;
+    unit_cost_pct[i] = unit_cost_adj[i] = 100;
   }
 
   city_init_tile_mods(pcity);
@@ -1930,6 +1941,19 @@
 	defensefppct[iter.imeff->aff_unit] = defensefppct[iter.imeff->aff_unit]
 	  				     * amount / 100;
         break;
+      case EFT_UNIT_COST:
+	unit_cost_adj[iter.imeff->aff_unit] += amount;
+	break;
+      case EFT_BUILDING_COST:
+	impr_cost_adj += amount;
+	break;
+      case EFT_UNIT_COST_PCT:
+	unit_cost_pct[iter.imeff->aff_unit] =
+	    unit_cost_pct[iter.imeff->aff_unit] * amount / 100;
+	break;
+      case EFT_BUILDING_COST_PCT:
+	impr_cost_pct = impr_cost_pct * amount / 100;
+	break;
       case EFT_TAX_BONUS:
 	update_bonus(tax_bonus, amount, &iter, TRUE);
 	break;
@@ -2056,11 +2080,13 @@
   pcity->poppoladj = poppoladj;
   pcity->prodpoladj = prodpoladj;
 
+  pcity->impr_cost_pct = impr_cost_pct * impr_cost_adj / 100;
   for (i = 0; i <= UCL_LAST; i++) {
     pcity->defensepct[i] = defensepct[i];
     pcity->attackpct[i] = attackpct[i];
     pcity->attackfppct[i] = attackfppct[i];
     pcity->defensefppct[i] = defensefppct[i];
+    pcity->unit_cost_pct[i] = unit_cost_pct[i] * unit_cost_adj[i] / 100;
   }
 }
 
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/city.h freeciv-patched/common/city.h
--- freeciv-cvs/common/city.h	2003-07-24 17:04:53.000000000 +0100
+++ freeciv-patched/common/city.h	2003-07-24 17:05:30.000000000 +0100
@@ -266,6 +266,10 @@
   /* pollution modifiers from city improvements */
   int poppoladj, prodpoladj, poladj;
 
+  /* cost modifiers */
+  int impr_cost_pct;
+  int unit_cost_pct[UCL_LAST + 1];
+
   /* the totals */
   int luxury_total, tax_total, science_total;
   
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/improvement.c freeciv-patched/common/improvement.c
--- freeciv-cvs/common/improvement.c	2003-07-24 17:05:30.000000000 +0100
+++ freeciv-patched/common/improvement.c	2003-07-24 17:05:30.000000000 +0100
@@ -158,7 +158,11 @@
   "Force_Happy",
   "Unit_Attack",
   "Unit_Attack_Firepower",
-  "Unit_Defend_Firepower"
+  "Unit_Defend_Firepower",
+  "Unit_Cost",
+  "Building_Cost",
+  "Unit_Cost_Pct",
+  "Building_Cost_Pct"
 };
 
 /**************************************************************************
@@ -342,6 +346,15 @@
 }
 
 /**************************************************************************
+  Returns the effective value of the improvement, after applying any
+  cost modifiers.
+**************************************************************************/
+int improvement_value_adjusted(Impr_Type_id id, struct city *pcity)
+{
+  return improvement_value(id) * pcity->impr_cost_pct / 100;
+}
+
+/**************************************************************************
 ...
 **************************************************************************/
 bool is_wonder(Impr_Type_id id)
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/improvement.h freeciv-patched/common/improvement.h
--- freeciv-cvs/common/improvement.h	2003-07-24 17:05:30.000000000 +0100
+++ freeciv-patched/common/improvement.h	2003-07-24 17:05:30.000000000 +0100
@@ -183,6 +183,10 @@
   EFT_UNIT_ATTACK,
   EFT_UNIT_ATTACK_FIREPOWER,
   EFT_UNIT_DEFEND_FIREPOWER,
+  EFT_UNIT_COST,
+  EFT_BUILDING_COST,
+  EFT_UNIT_COST_PCT,
+  EFT_BUILDING_COST_PCT,
   EFT_LAST	/* keep this last */
 };
 
@@ -402,6 +406,7 @@
 struct impr_type *get_improvement_type(Impr_Type_id id);
 bool improvement_exists(Impr_Type_id id);
 int improvement_value(Impr_Type_id id);
+int improvement_value_adjusted(Impr_Type_id id, struct city *pcity);
 bool is_wonder(Impr_Type_id id);
 const char *get_improvement_name(Impr_Type_id id);
 
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/unit.c freeciv-patched/common/unit.c
--- freeciv-cvs/common/unit.c	2003-07-24 17:04:53.000000000 +0100
+++ freeciv-patched/common/unit.c	2003-07-24 17:05:31.000000000 +0100
@@ -201,15 +201,19 @@
 **************************************************************************/
 bool unit_can_help_build_wonder(struct unit *punit, struct city *pcity)
 {
+  int imp_value;
+
   if (!is_tiles_adjacent(punit->x, punit->y, pcity->x, pcity->y)
       && !same_pos(punit->x, punit->y, pcity->x, pcity->y))
     return FALSE;
 
+  imp_value = improvement_value_adjusted(pcity->currently_building, pcity);
+
   return unit_flag(punit, F_HELP_WONDER)
          && punit->owner == pcity->owner
          && !pcity->is_building_unit
          && is_wonder(pcity->currently_building)
-         && pcity->shield_stock < improvement_value(pcity->currently_building);
+         && pcity->shield_stock < imp_value;
 }
 
 
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/unittype.c freeciv-patched/common/unittype.c
--- freeciv-cvs/common/unittype.c	2003-07-24 17:04:53.000000000 +0100
+++ freeciv-patched/common/unittype.c	2003-07-24 17:05:31.000000000 +0100
@@ -223,6 +223,25 @@
 }
 
 /**************************************************************************
+  Returns the effective value of the unit, after applying any
+  cost modifiers.
+**************************************************************************/
+int unit_value_adjusted(Unit_Type_id id, struct city *pcity)
+{
+  int i, val;
+  struct unit_classes aff_unit;
+
+  get_unittype_classes(id, &aff_unit);
+  val = unit_value(id);
+  for (i = 0; i <= UCL_LAST; ++i) {
+    if (is_unit_class_in_set(i, &aff_unit)) {
+      val = val * pcity->unit_cost_pct[i] / 100;
+    }
+  }
+  return val;
+}
+
+/**************************************************************************
 ...
 **************************************************************************/
 int unit_pop_value(Unit_Type_id id)
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/common/unittype.h freeciv-patched/common/unittype.h
--- freeciv-cvs/common/unittype.h	2003-07-24 17:04:53.000000000 +0100
+++ freeciv-patched/common/unittype.h	2003-07-24 17:05:31.000000000 +0100
@@ -205,6 +205,7 @@
 bool is_unit_class_in_set(Unit_Class_id id, struct unit_classes *classes);
 
 int unit_value(Unit_Type_id id);
+int unit_value_adjusted(Unit_Type_id id, struct city *pcity);
 int unit_pop_value(Unit_Type_id id);
 
 const char *unit_name(Unit_Type_id id);
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/doc/README.effects freeciv-patched/doc/README.effects
--- freeciv-cvs/doc/README.effects	2003-07-24 17:05:30.000000000 +0100
+++ freeciv-patched/doc/README.effects	2003-07-24 17:05:31.000000000 +0100
@@ -244,6 +244,22 @@
 "Unit_Veteran"	- all units of class .aff_unit produced are veteran
 		  units
 
+"Unit_Cost"	- increase the cost of building a unit of class
+		  .aff_unit in the city by AMOUNT percent
+		  (multiple effects are additive)
+
+"Building_Cost"	- increase the cost of building an improvement
+		  in the city by AMOUNT percent
+		  (multiple effects are additive)
+
+"Unit_Cost_Pct"	- multiply the cost of building a unit of class
+		  .aff_unit in the city by AMOUNT percent
+		  (multiple effects are multiplicative)
+
+"Building_Cost_Pct"- multiply the cost of building an improvement
+		  in the city by AMOUNT percent
+		  (multiple effects are multiplicative)
+
 "Upgrade_One_Step"- upgrade one obsolete unit per turn, stepping to each
 		  intermediate type; chance to upgrade each unit is
 		  AMOUNT percent
diff -Nur -Xfreecivdiff.ignore freeciv-cvs/server/cityturn.c freeciv-patched/server/cityturn.c
--- freeciv-cvs/server/cityturn.c	2003-07-24 17:05:30.000000000 +0100
+++ freeciv-patched/server/cityturn.c	2003-07-24 17:05:31.000000000 +0100
@@ -951,6 +951,7 @@
 static bool city_build_building(struct player *pplayer, struct city *pcity)
 {
   bool space_part;
+  int imp_value;
 
   if (pcity->currently_building == B_CAPITAL) {
     assert(pcity->shield_surplus >= 0);
@@ -970,7 +971,9 @@
 						   currently_building));
     return TRUE;
   }
-  if (pcity->shield_stock >= improvement_value(pcity->currently_building)) {
+
+  imp_value = improvement_value_adjusted(pcity->currently_building, pcity);
+  if (pcity->shield_stock >= imp_value) {
     if (pcity->currently_building == B_PALACE) {
       city_list_iterate(pplayer->cities, palace)
 	  if (city_got_building(palace, B_PALACE)) {
@@ -991,9 +994,8 @@
       space_part = FALSE;
       city_add_improvement(pcity, pcity->currently_building);
     }
-    pcity->before_change_shields -=
-	improvement_value(pcity->currently_building);
-    pcity->shield_stock -= improvement_value(pcity->currently_building);
+    pcity->before_change_shields -= imp_value;
+    pcity->shield_stock -= imp_value;
     pcity->turn_last_built = game.year;
     /* to eliminate micromanagement */
     if (is_wonder(pcity->currently_building)) {
@@ -1053,9 +1055,13 @@
 **************************************************************************/
 static bool city_build_unit(struct player *pplayer, struct city *pcity)
 {
+  int unit_val;
+
   upgrade_unit_prod(pcity);
 
-  if (pcity->shield_stock >= unit_value(pcity->currently_building)) {
+  unit_val = unit_value_adjusted(pcity->currently_building, pcity);
+
+  if (pcity->shield_stock >= unit_val) {
     int pop_cost = unit_pop_value(pcity->currently_building);
 
     /* Should we disband the city? -- Massimo */
@@ -1088,8 +1094,8 @@
 
     /* to eliminate micromanagement, we only subtract the unit's
        cost */
-    pcity->before_change_shields -= unit_value(pcity->currently_building);
-    pcity->shield_stock -= unit_value(pcity->currently_building);
+    pcity->before_change_shields -= unit_val;
+    pcity->shield_stock -= unit_val;
 
     notify_player_ex(pplayer, pcity->x, pcity->y, E_UNIT_BUILD,
 		     _("Game: %s is finished building %s."),