Go and pick it up in person or have someone else you "trust" do it for you.
I have so far traveled to blue mountains and proabably tassie in next couple of weeks looking at turbo kits...as handing over 2k plus for no guarantee is of concern.
I also had someone look at something for me in Darwin, however here I got a little stooged...the guy told me it was shagged, so I wouldnt buy it, then bought it himself. LOL
There should be a service that facilitates interstate sales and checks products for condition then carries out financial transactions and organizes secure postage for us. This would certainly weed out the dodgy ppl, but I guess inturn increase prices...which defeats the reason for the 2nd hand trade anyway. haha
My tip, if you dont trust it, dont do it.