Picking the right ads and payout

This is something that is hard to get the hand off. For example, today I got a $75.00 purchase from an affiliate link. My payout, was about $4 and some change. You may say "not bad" and it isn't as I was paying $.80 for 7,200 impressions using Project Wonderful.

Thing is I am still unsure of using % based ads or set amount. It's a fine line and can make you or break you. Not seeing too much on my POF so far but I have only spent $0.69 for 8,000 impressions and they are all high paying offers.

Time will tell whether I stay with POF or Project Wonderful