It's about this artist named J.S.B. Boggs that I first heard about on the PBS program Egg. He draws money. Then he goes to restaurants and trades his "money" for a meal, insisting on change from the face value of the drawing if the owner agrees to the trade. He even gets a receipt. Then he takes the receipt, frames it with the restaurant address, and hangs it in his gallery. Serious collectors of art see the receipt, then go to the restaurant owner to try and buy the drawing from them. If they succeed, they then spend a few thousand buying the receipt, so as to own the complete piece of art.
If you owned a restaurant and some lunatic wanted to pay for his meal with a drawing of a fifty dollar bill and insisted on change for it, would you do it? I would. But I wouldn't part with such a unique piece of performance art unless the collector who came to me was offering at least $500 for it. Real dollars. Net gain: $450. Heh.