Power Apps Community Plan: a free development environment for individual use

 Now you can create a developer instance for learning and creating power apps. It will not expire unlike a trail instance.

Use the below link to know more about this.

https://docs.microsoft.com/en-us/powerapps/maker/dev-community-plan

Use the below link to create your developer instance.

https://powerapps.microsoft.com/en-us/communityplan/