The app is very easy to use: once installed on your Android terminal, you just have to visit it once a day to see which app is free, and if you like it, you can download it without paying a Euro.
Occasionally, instead of a free app, you will be offered a 90% discount on the original sale price. This doesn't happen too often, and when it does, it is usually for fairly high priced apps.
AppGratis is a really interesting tool for any Android user. It only takes up a couple of megabytes on your terminal, and lets you download lots of normally paid for apps and games for free.