This phrase really gets on my nerves - it's become a common response to "what's it worth" - ridiculous as the buyer may well put the item back up for sale the following day ("flip it!" ) and get several hundreds/ thousands more.
So which is it? The first amount? The second? An average of the two?
I advertise my gear for what I think it's worth, taking into account condition -v- similar items I've seen sold. Basically what I think would be a fair price to pay if I was buying it. Want to buy it at that price? If the answer is "no" then I'll hold on to it till somebody will and you can find one at a price you are prepared to pay (and take the risks of the unknown).
My brother sells antiques and is often "lowballed" - his attitude is "fucck 'em" - when they can't find it at the price they want to pay they'll either come back or they can go without.