I have been using this app for a few months now and already racked up quite a few coins. The app basically tracks your outdoor steps and pays you in "sweat coins". Think bit coins but without the high value. Each day there are offers available for free items to trade in your sweat coins for. A lot of these are fitness based such as healthy eating products, water bottles or tshirts etc. It's basically something for nothing. This isn't like a survey site where it takes you years to earn a ten pound voucher, it's easy to earn them by just having your phone on you. If you forget to open the app before your walk it does everything itself once you hit 500meters. Again basically something for nothing. Have a read of the reviews in the App Store, they speak for themselves.