I Want to Sell Pop-up's On my Site How do i monitor them??

hi,

i have a site that get's around 20k traffic per day,
and i wanna sell pop-up's personally without going through some third party,

i know pop-up scripts,
but how do i monitor them??

like, if a customer wanted 10k traffic??
how do i know i have already delivered 10k traffic to them??

Thanks