Looking for a good deal on an airline ticket? Or maybe a car? Or any number of other products? Priceline.com would like to do the looking for you. Billed as a “buying service,” Priceline asks you what price you’re willing to pay—and then asks airlines (or whoever else) if they’ve got a ticket they’re willing to sell you at that price. Priceline.com has a new business model, and it’s gotten a lot of attention over the years, given the you-name-the-price buying system and the help of the company’s celebrity spokesman, William Shatner.