Warehouse clubs have introduced millions to low prices via buying in bulk, but applying the power of the group is now getting discounts on everything from restaurants to sporting events.

I stumbled upon Groupon fairly recently. One of those "heard it from a friend who heard it from a friend" kind of things. I don't usually go for coupons, too many hoops to jump through, but one buy and I was hooked.

Each day, Groupon offers up a single deal. I've gotten $50 restaurant gift certificates for $20, and been tempted by four, one hour massages for just $60. Each offer is good for one day only or until it sells out. There's a minimum that must be sold for the discount price to kick in, hence the "group" part of the program, but no one gets charged until that actually happens. Right now Groupon serves Chicago, New York, Boston and Washington, DC and San Francisco. Atlanta and Los Angeles are next.

The best part is you get to buy only what you think you can use, unlike certain coupon books. Dental services, spa packages even tickets to a private rooftop to watch the Chicago Cubs play at Wrigley Field. It's from the founder of The Point, a site intended to marshal the masses to push social issues over the tipping point. Applied to consumer purchases, it's a novel approach, and the businesses that participate say they get lots of new customers. According to Reuters, BriteSmile in Chicago offered $600 worth of tooth whitening services for $189, and got 220 new customers. More recently, the same deal netted 700 new customers.

Group shop, apparently, is taking off. A similar concept called Buy With Me just launched in Boston, with more cities pending.