I hope some of you guys that are running Admob ads in your apps can help me with this. I dont understand how to calculate the amount of money you make each time an ad is displayed. There is very little information about this on the Admob site.

How much money does Admob pay to publishers for clicks and impressions? are these amounts different? How are they calculated?

What exactly do eCPM, CPC and CTR mean?

What kind of figures would you hope to see for an app with a small userbase, say 200-500 users?

Thanks