Hi there,

i wrote an android app which is basically the same with AppInventor and i offer a project kit with the complete source and an ebook which shows the complete process of developing this app. Also i´ve included
a tutorial how anyone can monetize the app by placing ads in it ( free ).

Just take a look an it and let me know what you think about it

https://play.google.com/store/apps/details?id=appinventor.ai_smacri70.CryptocoinRotator

if you are interested in the project kit, just reply or send an email at smacri70@gmail.com

I also offer a CaptchaToolkit for AppInventor which allows to protect informations etc. by two different text captchas and two different voice captchas.