2 non railway items listed recently, 1 was listed for £100 which was about right, offer of £85 which was turned into £93, both happy and I got good feedback so purchaser was satisfied.
2nd item listed for £375 (I expect to get about £330-350 ish) offer comes in for £40, suggested that he try again nearer the listed price and counter with £365, replies with £42 so offer deleted and person blocked.
I have no problem with an opening cheeky offer, but the 2nd has to be realistic.