Instructor Albert Lo kicks off the course by explaining how to set up your existing app for in-app purchases by modifying the UI. Next, he acquaints you with the Gradle build system, and shows how to leverage it to support in-app purchases. Albert then provides an overview of the billing process, and shows how to define your digital products, and use the Google in-app library to query purchased items, launch the purchase flow from both one-time purchases and subscriptions, and handle responses.

Topics include:
* Setting up an existing app for In-app Billing
* Working with the Gradle build system
* Registering a keystore
* Defining and accessing Gradle build configuration parameters from code
* Setting up a payments merchant account
* Setting up IAB test accounts
* Publishing the APK to Google Play alpha
* Defining managed products and subscription products
* Implementing In-app Billing
* Testing in-app purchases