You need to lower your rates and to use escrow.
I can't really go much lower than 12% for small amounts. With transaction fees, market fluctuations and the risk of being scammed I am taking, I think 12% is fair. Most sellers use 15%. If I go with 10% or less I don't see how I will make any profit at all unless I am selling larger amounts like $150+.
Yes I've already had lots of scam attempts since posting this thread. I very easily spot scams, so no worries there.