We'd like players to be able to purchase multiples of an item with a single in-app purchase. For example, say that one of our virtual goods is an "ammo box", and we want the player to be able to purchase 3 ammo boxes for $1.
The in-app purchase documentation for GameSparks doesn't describe how to control the quantity of an item that is purchased using in-app purchase. Using the above example, how would we let the player purchase three ammo boxes in a single $1 in-app purchase? What if we also wanted them to be able to purchase ten ammo boxes for $2?