- Converted Heartstone, Power Artifact and Training Grounds to StAb ReduceCost.

res/cardsfolder/h/heartstone.txt

@@ -2,7 +2,7 @@ Name:Heartstone
 ManaCost:3
 Types:Artifact
 Text:no text
-K:CostChange:Player:Less:1:Ability:All:Creature:TargetInPlay:Activated abilities of creatures you control cost 1 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
+S:Mode$ ReduceCost | ValidCard$ Creature.YouCtrl | Type$ Ability | Amount$ 1 | MinMana$ 1 | AffectedZone$ Battlefield | Description$ Activated abilities of creatures you control cost 1 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
 SVar:Rarity:Uncommon
 SVar:Picture:http://www.wizards.com/global/images/magic/general/heartstone.jpg
 SetInfo:STH|Uncommon|http://magiccards.info/scans/en/sh/128.jpg

res/cardsfolder/p/power_artifact.txt

@@ -2,8 +2,8 @@ Name:Power Artifact
 ManaCost:U U
 Types:Enchantment Aura
 Text:no text
-K:CostChange:Player:Less:2:Enchanted:All:Artifact:TargetInPlay:Enchanted artifact's activated abilities cost 2 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
 K:Enchant artifact
+S:Mode$ ReduceCost | ValidCard$ Artifact.EnchantedBy | Type$ Ability | Amount$ 2 | MinMana$ 1 | Description$ Enchanted artifact's activated abilities cost 2 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
 A:SP$ Attach | Cost$ U U | ValidTgts$ Artifact | AILogic$ Pump
 SVar:RemRandomDeck:True
 SVar:Rarity:Uncommon

res/cardsfolder/t/training_grounds.txt

@@ -2,7 +2,7 @@ Name:Training Grounds
 ManaCost:U
 Types:Enchantment
 Text:no text
-K:CostChange:Player:Less:2:Ability:All:Creature:TargetInPlay:Activated abilities of creatures you control cost up to 2 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
+S:Mode$ ReduceCost | ValidCard$ Creature.YouCtrl | Type$ Ability | Amount$ 2 | MinMana$ 1 | AffectedZone$ Battlefield | Description$ Activated abilities of creatures you control cost 2 less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.
 SVar:Rarity:Rare
 SVar:Picture:http://www.wizards.com/global/images/magic/general/training_grounds.jpg
 SetInfo:ROE|Rare|http://magiccards.info/scans/en/roe/91.jpg

src/main/java/forge/card/staticability/StaticAbilityCostChange.java

@@ -24,6 +24,7 @@ import forge.card.cardfactory.CardFactoryUtil;
 import forge.card.mana.ManaCost;
 import forge.card.spellability.SpellAbility;
 import forge.game.player.Player;
+import forge.game.zone.ZoneType;
 
 /**
  * The Class StaticAbility_CantBeCast.
@@ -80,6 +81,10 @@ public class StaticAbilityCostChange {
      */
     public static ManaCost applyReduceCostAbility(final StaticAbility staticAbility, final SpellAbility sa
             , final ManaCost originalCost) {
+        //Can't reduce zero cost
+        if (originalCost.toString().equals("0")) {
+            return originalCost;
+        }
         final HashMap<String, String> params = staticAbility.getMapParams();
         final Card hostCard = staticAbility.getHostCard();
         final Player activator = sa.getActivatingPlayer();
@@ -101,6 +106,9 @@ public class StaticAbilityCostChange {
         if (params.containsKey("Type") && params.get("Type").equals("Ability") && !sa.isAbility()) {
             return originalCost;
         }
+        if (params.containsKey("AffectedZone") && !card.isInZone(ZoneType.smartValueOf("AffectedZone"))) {
+            return originalCost;
+        }
 
         if (!"WUGRB".contains(amount)) {
             int value = 0;
@@ -111,8 +119,12 @@ public class StaticAbilityCostChange {
             }
 
             manaCost.decreaseColorlessMana(value);
+            if (manaCost.toString().equals("0") && params.containsKey("MinMana")) {
+                manaCost.increaseColorlessMana(Integer.valueOf(params.get("MinMana")));
+            }
         }
 
+
         return manaCost;
     }
 }