Where to find Google App Maker personal version for learning purposes?
According to the product page,
App Maker is included with G Suite Business and Enterprise editions as well as with G Suite for Education. If you would like to use Google App Maker and don't have a G Suite account, one of the lowest-cost options is to subscribe to G Suite Business, purchase your own domain name, and create the smallest-tier Google Cloud SQL deployment. Unfortunately none of these are free.
EDIT: Please note that App Maker is being discontinued, and has been replaced with AppSheet. It can be purchased separately, or is included with Google Workspace Enterprise.