http://paypopup.com/ Trust me. they pay. i earned something like $160 and they sent me a check for $189 lol. dont know how that got mixed up but it happened. Their CPM (1000 impressions) rate is $1.80. plus their ads are pop-unders so they arent shown and they automatically pop-up. idk if anybody else has used them but to me they are the best! only posting this to help other ppl out. realize i didnt post my referral link. i just want everybody to earn some revenue. also i am very new to these forums but have visited them plenty in search of answers!
i havent had good luck with paypopups ads. They had malicious programs trying to run. Thats the only bad thing i can say about them. Other than that, i would have stayed with them, but as a webmaster you cant allow that stuff on your site.