Ok, so- Imagine you're playing Cake Wars and you just messed up, buying an extra pair of diamond boots, wasting 10 emeralds. Or, you found an extra diamond chestplate in a chest and need emeralds. This is where my idea comes into play. This concept is that, for example, you can have a pair of diamond boots and can "return" it to the shop and be reimbursed for 10 emeralds, the price of the item. This could save a lot of frustration when you mess up and buy an extra item or two.