Depends on what your promoting and what type of traffic you buy. Clicked traffic from high quality countries matching the product you are selling has a higher rate of conversion than popunder, blind, skimmed. You need to buy the right traffic then analyze to make sure you received what you paid for and if so increase your ad spend, if not then move on to the next until you find what traffic has the highest productivity/sales for your product. Quality usually doesn't come in bulk so takes a bit of analyzing to determine what works the best.
I buy geo targeted text links from
Traffic-Out
I buy from sites that match what I'm selling with majority of high quality country traffic from
Juicy Ads
Just trying out
Plug Rush since the relaunch so verdict still out, like the system so far just haven't had time to analyze against the first 2 yet.
I also buy hardlinks from webmasters. Good Luck
