Thanks for your reply. Actually you don't have to sign up. I should have made this more clear in this post or even in the app. When you click on "One week free trial" the app will save a boolean on User Defaults which saves the date of you taking the free trial. So no sign up is needed. So basically every time you delete the app you can get a free week again. I wanted to implement some sort of in app purchase but also let as many people as possible try the app. I'm thinking about making the app completely free with the next version. My most important point here is to get a feedback from people in the field.