If marketing is the art of selling products at higher prices than they are intrinsically worth then one of the keys is to keep supply lower than demand. Selling luxury Swiss watches is an example. From the Economist, November 12th, 2009, Salesman of the Irrational; tells the story of Jean-Claude Biver, a master of supply and demand.

"Hublot's success stems in part from Mr Biver's penchant for rationing his products. He was careful to restrict supply when business was booming, delivering only seven watches, say, when ten were ordered. Jewellers pay cash for stock, so it seems foolish not to sell as many watches as possible. Yet for Mr Biver it is an essential strategy. "You only desire what you cannot get," he says. "People want exclusivity, so you must always keep the customer hungry and frustrated."

Mr Biver developed a new, backward-looking slogan for the firm: "Since 1735 there has never been a quartz Blancpain watch. And there never will be." It turned out to be an industry-changing move.

Biver nonetheless relies on the existence of free-spending consumers with a penchant for showing off. At the best of times, he freely admits, it is hard to justify spending $100,000 on a watch. But the fact that they keep time well, he hopes, will continue to serve as "the little bit of rationality that lets you sell the irrational."