Looking for a source of deals that covers everything from cupcakes to yoga? Groupon is your answer. The service puts a mob of potential buyers in control, letting them decide whether or not the deal is on. Users can view deals by location, or sort the ones they’ve already signed up for by expiration date. You don’t even have to print out coupon after coupon: The Groupon app lets you buy and redeem deals directly from your smartphone. Plus, a handy section called Groupon Now Deals lets you survey nearby offers that you can buy and use immediately.