Hi there, I make a list of PPC site. If you already used any of this kindly suggest which one will be good for product or service promotion. DigitalPoint Ads Facebook Ads Twitter Ads Google Adwords Yahoo Ads Bing Ads 7Search BIDVERTISER Chitika TLVMedia ADEngage looksmart 50onred web.com AolAdvertising Affinity Ero Advertising Admange Criteo GlobalTakeOff infolinks Clicksor
obviously would go with Facebook Ads, Facebook great & biggest social network which has millions user from all over the world & still uncountable peoples join Faceboook, So Facebook Ads is best for PPC campaign
LifestreetMedia & Redirect.com are two others you could add. Obviously, Adwords is going to be the most expensive. If you're looking for the best money value it's probably in some of the smaller guys.
I would have said Facebook and Google are the best PPC sites, until recently. A few weeks ago I run a Twitter PPC campaign and I achieved less then 1 cent clicks and got really targeted traffic who where ready to buy. Very under utilised PPC site in my opinion.