- Fixed costChanges not applying to AI spells with a cost of 0.

src/main/java/forge/card/cost/CostPayment.java

@@ -292,6 +292,10 @@ public class CostPayment {
         final Card source = this.ability.getSourceCard();
         final ArrayList<CostPart> parts = this.cost.getCostParts();
 
+        if (this.getCost().getCostMana() == null) {
+            parts.add(new CostMana("0", 1));
+        }
+
         // Set all of the decisions before attempting to pay anything
         for (final CostPart part : parts) {
             if (!part.decideAIPayment(this.ability, source, this)) {