Pop Under Advertising Network?

A good one is Adversal if you can get accepted.

thanks, what's the largest one?

Adversal is the largest far as I know. I personally use to sell there pop-unders. It is cheaper if you just create a publisher account and set your accounts up to your websites. I did not say that.

I can help you if you want.

Like take bulk for instance which is run of network runs about .67 per 1k but a reseller will charge you about 2.00 per 1k.