Basically anywhere on property that will take a debit or credit card. Small vendors like soda carts and such won't take them. You need cash for those. Cabs will not take them, obviously either. Not sure about places like Virgin Megastore and others in Downtown Disney that aren't Disney. Also a question just came to mind. How does one get cash with a Key to the World card? I doubt you can put them in an ATM...Can you? Or can you get an advance from Guest Relations?