Let's hack with lucky patcher

Step 1: First of all you have to download Lucky Patcher on Android Mobile. 

Step 2: You have to install it.

Step 3: Open the application.

Step 4:It will show all the apps and games present in your phone.

Step 5:  Then click on the game you want to make free in app purchase.

Step 6:Then tap on open  menu of options.

Step 7: Then click on create modified APK file.

Step 8: Then tap on “Apk rebuilded for inApp And LVL emulation”.Then  it takes few minutes and app is rebuilded.