Change Dispenser
A vending machine at work would still operate after hitting the coin return button. Anyone could pick an item then hit the coin return to get their money back plus the item. If you think that is awesome, it gets better.
Say you put four quarters in the machine and repeatedly press the change return button, you will get four quarters each time you press it. I completely emptied the vending machine one night after everyone went home, so I basically have free laundry for a few months.