Most of the website owners do not prefer Pop under ad network.
Here are best pop under ad networks to your sites.
it is the best Pop under ad networks pays $4 per thousand unique views. i have just checked it and was very success with it.
it is also one of the best Pop under ad network that pays $2 per thousand unique views.
3. INFINITY ADS.COM
it is also best pop under ad network that pays $ 1.8 per thousand page views.
it is also an Pop under ad network .