is there something like "in-app-purchase" in android?
the company I am working for is using this feature within their iphone app.
let me explain how it works:
1) you download the gold app and pay some money (the silver app is for free)
2) this grants you 1 month of full usage
3) inside this month you can pay another little money and you get another month
4) you dont need to download the gold app again