Uh, it's pretty obvious in the game which in-app purchases can be unlocked. But you're right, there shouldn't be any cost to the game at all. God forbid someone make money off of their hard work. 
Why not ask your fellow community members what the IAP entails? Many have already responded with IAP information. This would require the same amount of effort as your first post in the thread and you'd be engaging with the same users you care enough about to warn of potential monetary threats.
Uh, it's pretty obvious in the game which in-app purchases can be unlocked. But you're right, there shouldn't be any cost to the game at all. God forbid someone make money off of their hard work.![]()
Never said that. I said be honest about it. Don't call it free and then make people pay once they start playing. Either make a demo version, or call it TRIALWARE or make it clear that it's in-app supported. DON'T call it FREE. Especially don't say, "FREE for a limited time!"
This is Polymer if you get it right now.FREE -- You can download it and play without having to spend a penny on it.
This is Polymer if you wait until the limited time is over.PAID -- You pay so much for the game, and can complete it normally without having to pay anything more.
You can go to the IAP store to unlock all or any combination of modes, pieces, and themes you want OR grind along in each of the game's unlocked modes to unlock whatever the game determines is your next reward. Each game mode works toward unlocking a different item. A cool system if you're patient but maybe a bit annoying if the next thing to be unlocked is not something you're interested in (like in my current run, any games I play of the 2 min game will be working toward unlocking a Black and White theme although I'd much rather open new game modes and pieces).
Version 3 adds a fun twist on the classic game with new downloadable themes and challenging new puzzle book campaigns. But this is not a freemium app. Sudoku Book’s core functionality is all included. It has unlimited free play in all levels and all the same features as the previous version plus more.