what is the best Ad server PHP system script?

i mean so i can allow anyone to buy text/banner ads on my multiple sites in easy and quick way
Moreover itshould be automatd with paypal. If member do not renew ontime, ad is disabled automatically..

So far i find this scipt which appears to do this job: but i just tried demo, did not installed it.
1) http://calendarscripts.info/ad-management-software.html
2) http://orbitopenadserver.com/