For now I have tried to solve it by removing all BUY buttons from the interface but one - on welcome screen, that buys you everything forever - which is effecti

For now I have tried to solve it by removing all BUY buttons from the interface but one - on welcome screen, that buys you everything forever - which is effectively turning app into 'pro' version without ads, offers, just pure content. IAP is new to me, but from what I read it is the most effective way to monetize. Needs to be done nicely, though.