The online couponing mecca wants to make sure you never willingly walk past a bargain. Allow RetailMeNotto access to your location, and it will send you alerts to nearby sales and discounts. You can also tell the app which mall or shopping center you're planning to visit, and it will surface deals in that location ahead of time. Present in-store coupons to the cashier on your phone screen, and save some trees, too. Feeling peckish? The app also features discounts from popular restaurant chains, so you can save some scratch while planning your next move.