Yeah, real revenue doesn't kick in until you get impressions in the millions.
With that said, a CPM of .84 cents and a fill rate of 60 % or higher, if you generate 1 million impressions a day you will make:
60% of 1,000,000 = 600,000 actual ads served (in regards to a fill rate of 60%).
600,000 ads served / 1000 (CPM) = 600
so 600 dollars with 84 cents to the dollar = 504 dollars a day.
If you keep that up for 3 months that is ~45,000 dollars.
This is with only 1 million impressions a day.
If you take a game that can generate 10 impressions per play session, then you can lower your user base 100,000 individual players.
A huge app, with 1 million plus players per day, things like Don't tap the white tiles, make them fall, or flappy birds, could feasibly make thousands of dollars every day.
"From where do you come barbarian, and by what are you called?" Gasped the complying wench, as Grignr smothered her lips with the blazing touch of his flaming mouth.