Hi Woz,
I hear what you are saying and with these high-balled prices it just gives the next idiot the ammunition to then think that's what their item will sell for thus they'll be asking another outrageous figure.
I've sold tons of gear on the ol' Gumtree, but I always ask what would be a fair and market value of the item in question. Wankers that want to cut you in half or even less just get ignored. I guess my marketing strategies and what I sell just doesn't attract that sort of clientele.
Now if you're selling filthy dirty looking car parts then you're just leaving yourself open to these sorts of low lifes.
