There may be several reasons why you cannot make in-app purchases.
If you don't see a price or there's a wrong one, it might be because your game cannot connect to the store.
In that case:
- check that your device has a stable internet connection
- go to your device's ‘Settings’ and make sure the 'Date & Time' settings are correct (preferably set it to 'Automatic')
- make sure you have a valid payment method in the Google Play, App Store or Amazon Appstore.
If the solutions above didn’t help, you could look for a solution here
For Amazon Kindle players