Groupon, arguably the leader in social buying, boasts branches representing 49 cities (although a bit more than half are currently active). Groupon was launched in November 2008 and raised $30 million in financing in December 2009. Groupon features a new deal every day; generally, the offer expires at midnight. Also, if you refer someone to the site and he or she subscribes within 72 hours, you'll receive a $10 credit when the person makes the initial Groupon purchase.
Available cities: Albuquerque, Atlanta, Austin, Baltimore, Boston, charlotte, Chicago, Cincinnati, Cleveland, Columbus, Dallas, Denver, Detroit, Fort Worth, Fresno, Houston, Indianapolis, Jacksonville, Kansas City, Las Vegas, London, Los Angeles, Louisville, Memphis, Miami, Milwaukee, Minneapolis/St. Paul, Nashville, New York, Oklahoma City, Omaha, Philadelphia, Phoenix, Pittsburgh, Portland, Raleigh/Durham, Sacramento, San Antonio, San Diego, San Francisco, San Jose, Seattle, Sioux Falls, St. Louis, Tampa, Toronto, Vancouver, Virginia Beach, Washington D.C.
Past deals: $45 truffle workshop ($88 value); $45 restorative massage ($100 value); $60 for a helicopter ride ($120 value).