Microsoft offer a free community plan for developers to play with PowerApps at no cost. I recommend you take a look at the following links and get yourself setup.
This training kit is for .NET developers to learn the development features of Dynamics CRM and help them build applications using Microsoft Dynamics CRM 2011 and CRM Online.
The training kit includes various resources such as
- Presentations – Presentation decks in PowerPoint (.pptx) format that you can use to learn the concepts.
- Videos – Video recordings of the presentation along with demos delivered by expert trainers.
- Hands-on Labs – Hands-on labs with detailed instructions and source code that will walk you through the various development features.
Download the training kit here: Dynamics CRM 2011 Developer Training Kit