By far the biggest and most popular of the regional deal sites, is available in just about every major U.S. city. The deals themselves are pretty random. I've been a Groupon subscriber for about a year now, and I've seen deals on everything from dental visits to "hiking yoga" classes.

Like Groupon, has a fairly wide reach over the United States and is available in most major cities, including Atlanta, Austin, Boston, Chicago, Denver, Los Angeles, and Minneapolis. LivingSocial is a great resource for budget travelers; many of the deals posted, like guided city tours or wine-tasting excursions, are aimed at tourists.

goes beyond simply offering up one deal per day. It features "Avalanche" deals, which get lower as more and more people purchase them.