Ad networks have minimum payout limits...
Revmob (if you use Payoneer) is just $50, or $200 for a bank payment.
Chartboost is $300 minimum.
This is fine for high performing apps, but often apps just don't perform very well so you are stuck with money earned that you will never see since you cannot make the minimum.
When you leave that ad network in frustration, they pocket your earnings...
This seems very unfair to me... does anyone have an opinion on this.. or know of good ad networks that hand over everything you earn... without problem?