A few tips...
I will not purchase unless the person has over 100 posts (has begun establishing himself as a member)
The bst rating is also another good indicator altho not the best since some don't sell very often or have never till that point. (look at my bst, does it mean i'm a bad seller because i've never sold on here before?)
Use an escrow service if possible. the escrow holds the money until you recieve the product and will not release the money until you've inspected and let them know you recieved and inspected. they do track the shipping so its known when recieved and after 3 days of reciept if you dont call the money is released.
If something just doesnt feel right about the deal, back out, no matter how mucyh you may want it.
guess my main concern is those with low post count who come here basically to sell then drop out of sight, as i said, the higher the post count the better.
not everyones a scammer and sometimes problems occur with shipping and life in general.