best spy tool for popunders?

What spy tool is best for popunder networks and mobile offers
I know of Adplexity but looking for a cheaper one to get started

I tried a free trial on one and while it showed me creatives when I went to check out the landing pages my computer freaked out at me about viruses
I am attempting to improve my CTR on pops and trying to see what offers or landing pages convert the best after click through

Anstrex

cool I think that was the tool I was looking for. What is the best place to get a coupon for it