This is my thought as well. Even at his previous $20-30/day seems quite reasonable. If the author could keep that sustainable, that's adding nearly $10k/year in

This is my thought as well. Even at his previous $20-30/day seems quite reasonable. If the author could keep that sustainable, that's adding nearly $10k/year in passive income, definitely not a figure to shy away from. If adding a $.99 IAP with a 2% conversion works as well, that would be even more. As an app developer, overall I feel these posts only encourage the current app store ecosystem of free or freemium.