How many starving artists have wished that merely by painting a plate of food, they could make one appear? The New York designers Justin Gignac and Christine Santora have found a way to do just that. Creators of the website Wants for Sale—and its charity-oriented sibling, Needs for Sale—the couple simply illustrates something they want, be it Buffalo wings, next month's rent check, or "instant street cred," and sell the Lichtensteinesque canvas online for the item’s exact cost ($12.70, $1,056.07, and £1, respectively—the last available only for purchase by Charles Saatchi himself).

There's a refreshing certainty to this way of valuing art. As Gignac says, "It takes the subjective out of it. We don’t make the prices—the companies do." And it has turned out to be an excellent vehicle for giving. With a price floor of $100, the Needs—a sink donated to Habitat for Humanity, footballs for Toys for Tots—have sold even more briskly than the Wants.