Top group-buying sites Top group-buying sites We hope your bargain-hunting urge isn't quelled yet, because group-buying websites have launched a worldwide Internet craze. Online shoppers can't get enough of getting more for a whole lot less. With tens of thousands of subscribers and growing, business is booming. The idea is simple: Provide your email address, receive emails with deals of the day, and click "buy" if you like it. Read on for a complete guide to the top group deal-getting sites around. Groupon Headquarters Where deals are available: More than 150 cities in the U.S. and Canada and 23 other countries. What makes it unique: Being the largest social buying site, Groupon has applications available for both the iPhone and Android devices, unlike many other sites of its kind. Just how valuable is it? In 2010, Groupon was said to be considering selling itself to Google for billions. Find out how much the deal was said to be worth. LivingSocial Headquarters Where...