Hi! I'm currently moving from an old inventory/rewards system (fully in-game, no IAP, soft currency) to Game Foundation (IAP, soft+hard currencies). However, in this system, some simple transactions (gold => item) have variable costs : item price depends on the amount in inventory (a ComputePrice() method reads the inventory). Hence each time you buy an item, its price increases. What would be the best approach implementing with GF, according to you? Thanks.