I have tested various apps that had AdMob in them over (goodness... a long time) the last 6 months or so. We are currently working with someone to test adding both AdMob and StartApp to his App Inventor app. The final app is coming together, unfortunately I still have to build parts of it by hand.
The current process is:
He sends us the source zip file. We add it to an Android app. I hand code a Screen0 that is like his Screen1 that has AdMob and StartApp included. When the app starts, it is on Screen0 and goes directly to his app's other screens, never touching Screen1.
It works!!!
I have to build the Android app with the custom Screen0 by hand.
His app has a nice background, some text and a button (or 6) to go to his other screens. That is not bad to generate by hand.
Hmmm
and it worked great for the simple app I gave it. We may... be able to use his App Inventor to Java service to get Screen1 => Screen0. However, his service is currently limited in what it can generate, and my tools do not use the Java Bridge.
Hmmm...
I think being able to have AdMob and other ad services would be a good thing for App Inventor.
Gary