Groupon runs on a similar concept ( http://www.groupon.com/faq http://www.groupon.com/faq ). A business can offer a discounted rate that's only valid if a cert

Groupon runs on a similar concept ( http://www.groupon.com/faq http://www.groupon.com/faq ). A business can offer a discounted rate that's only valid if a certain number of people commit to paying said discounted rate. I guess the rationale is that if you get a certain number of people in the door for the discounted rate, you'll have good odds of having enough of them buy other things that are not discounted that you can make your money back. Bar promotions are like that too, they'll have cheap beers and cheep foods to get people in the door who might also buy liquor or cocktails, or who might bring someone with them who will.