Its possible to put ads in android games from c2.
I was loooking for the same few days ago. And couldn't find answer. You can monetize with cocoonjs only if you have there premium account. But at this moment, its up to them to whom they give the premium account. So I looked into another options i.e. Intel XDK and phonegapp.
Unfortunately I searched only to found that intel xdk does not support ads right now either.
Now the phonegap. I Read on some sites that phone gap has some plugin for admob.. When i looked into the web and there site for cloud compilation i found that they don't have the plugin either.
But i managed to put admob ads on my android game. You can check the result here
I wanted to try all the options so i managed to make a test game and see if i can monetize it on mobile. The ad fill rate is also good.
Unfortunately i was not able to do it with the cloud complilation of either phonegap , cocoonjs or intelxdk. which i was preferring because i can get the apps for different platform at the same time with cloud compilation.
But i was able to do it using android sdk, eclipse , phonegap sdk and admob sdk.
if you search on web there are many references and tutorials that can tell you how to implement admob in phonegap with eclipse. But even with them i constantly struggled for week to do it properly.
I downloaded eclipse classic.
I found it much better to compile it myself because it gives me much better control over my application.
And i can even customize some actions like if i want to disable back or menu key or make them do something else. And i did it with just picking up codes from tuts and reference. I am sure you can do the same if you want. Now it wont take me more than half-1 hour to compile my game properly.