Wonder why they didn't hold out a little longer for a higher bid given that the $18,500 was the first and only bid placed...it's likely others would have come out to bid once they saw the bid, given a little more time - waiting even a few extra days could have made the difference.
Perhaps the seller needs cash right now and/or had been dealing with the buyer for awhile on the sale.
With all that said, he got a decent, fair price for it nevertheless
Ron