To be honest, if you are indie developer and you don't have very aggressive IAP like Clash of Clans or Throne Rush, there is no money from people that buy apps.

To be honest, if you are indie developer and you don't have very aggressive IAP like Clash of Clans or Throne Rush, there is no money from people that buy apps. I've seen cool indie games like TripleTown having trouble monetizing. I bet one could make more money from Ads (although I hate ads, I hate them less than whale-catching-IAPs). People using old devices can still click ads.