Android: This version of the application is not configured for billing through Google Play

Problem:
I followed the training class to setup the TrivialDrive sample for Google Play In-app Billing API Version 3. When I try to make a purchase, it shows

This version of the application is not configured for billing through Google Play. Check the help center for more information

Solution:
Sign your app with your release certificate.

Ref:
android - This version of the application is not configured for billing through Google Play - Stack Overflow