I know that many people have troubles with in-app purchases, so, here's the correct asset. In this asset you can find commented code how to:
-Make consumable purchases
-Make Non-consumable purchases
-Restore button to iOS games
-Comments on English and Russian (Русский)
If you have any questions, just ask and i can fix it in next versions of asset. If you do not understand something in code, write it in comments, and i try to explain it. If you do not understand code comments, write about it, and i try to explain it too.
NOTICE!: To use this asset you need buy Android or iOS export module!
-Added more comments in code!