On Amazon, if you want to open a store, you can open it for as long as you want, because after you register, they will not charge you any extra fees, nor will they force your store to be removed from the shelves. If you want to keep it open until no one buys your products, you can automatically declare bankruptcy, or just close the store. This is something you have to solve and decide for yourself. It's up to them to decide how long it will last.