There are situations when you might decide that you need to create 2 versions for your application: a free one and a paid one. So, in this tutorial, which is just a simple example (we will just set different colors for the 2 versions), we will see how to achieve this using flavors. Your project is certainly more complex, but I think that this tutorial will be ok for you to get the main idea of how you can do this.
First of all, you have to add 2 flavors: free and paid.in the build.gradle file which is located inside app folder (to not be confused with the build.gradle of your application which is outside of the app folder). Below is the code: