no. it gives you a chance to confirm after you click buy. so if you loose your crowns, too bad cause that means you need to be more wise next time. and if they make that feature, you could buy some stuff, put it back, buy some stuff, put that back later and so on. so it wouldn't be fair cause recycling crowns like that is recycling money. and plus if that happened lets say you bought a world with crowns. when you finish that world then you would need to get crowns to get the next world. you would just have to take the crowns back from purchasing that world, then you would just buy the other world. that would make them loose money which they don't want and we cannot change that.