Google Codelabs provides tutorials, guide, hands-on coding experience. Most of the codelabs have step by step guide to build a small application/adding a feature to the existing application. You can find about different topics here e.g. Android wear, Google Compute Engine & Google APIs on iOS etc.

Preview of one of the projects for your reference:

Accelerated Mobile Pages Advanced Concepts



Above is the screenshot of a project for your reference. On the left-hand side, you can find the steps and on the right-hand side, you can find the coding. 


Is Google Codelabs Free?

Google Codelabs is free. 


I hope you will find the solutions for your next project here!

Best of luck and happy coding :)