PlayBillingLibraryDemo
In-App Purchases in Android. Warning: you don't see billing dialog until upload build to Google Play.
— When you prepare project with In-App purchases for publishing to Google Play generate signed realise build and to publish it.
— Go to Play Console and add products for purchase.
— Wait 30-120 minute for update it on Google servers.
— Then you will see dialog billing and you can shop.