You can both build and play Power Apps for free by signing up for either a 30-day trial or a developer plan.

What power app can do?

What Does PowerApps Do? PowerApps provides a nice drag-and-drop user interface to allow you to add different controls (i.e. text field, choice field), media (images, video, camera controls for your phone), forms, and screens to construct a mobile app.

Is there a PowerApps desktop app?

To download the desktop version of PowerApps, you'll need to run the Microsoft Store App on a Windows 10 machine. From within the Store App, you can do a search on PowerApps and install the app from the product page.