The Swap-O-Matic vending machine is designed for users to give, take, or swap anything that fits inside the compartments. People have traded items like original art, poems, clothing, metro cards, etc. Lina Fenequito created the Swap-O-Matic as a student project at Parsons School of Design and is now trying to commercialize it. From CNN:
"The Swap-O-Matic recognizes that there is a thrill in getting things. The vending machine satisfies our desires for instant gratification, but it co-ops it and re-appropriates it to something that is a more sustainable method of acquisition, which is through swapping and trading," said Fenequito…
To use the machine, one simply has to enter their e-mail address on the screen and choose whether they would like to donate, receive, or swap an item. Since none of the items in the machine is assigned a value, all item transactions work on a credit system. As a new user, you're given three credits to begin with. A credit is earned each time you donate an item and it costs one credit to receive something. Swapping an item in the machine for something that you've brought doesn't require any credits.
"Swap-O-Matic: A vending machine for bartering with just about anything" (CNN)