I wrote this in response to a question on this web site’s Facebook page.
Someone asked if there was perhaps a paid version of App Inventor required for building apps that go in the Google Play store? No, there is no paid version.
You do not need a paid version of App Inventor; just use the Build .apk option to create an Android package file that can be installed on an Android device.
You can then submit your apps to the Google Play store. You will need to pay a US $25, one time only, to open a developer account. Thereafter, you may upload as many apps as you want to the Play store.
You’ll also need to create some screen snapshots and upload those as part of your app description in the Play store. There is much additional good information here – http://beta.appinventor.mit.edu/learn/reference/other/appstoplay.html
How to create App Inventor apps for the Google Play store is on my list of future tutorials. Unfortunately, I do not have time right at the moment to put that together – but eventually I will have something and describe the process in step-by-step detail!