I agree that once he offered it for sale and sold it his only choice was to man up and let the buyer have it.
I once sold a motorcycle and before the first guy got there second guy came by and offered twice as much.
Needless to say it was tempting but I stuck to my word. Having said that Eric knew he was getting a smoking deal yet felt compelled to not let seller know he was a fool for letting it go so cheap.
Everyone harps on the pickers but even they will tell a guy you're to cheap and I'm going to stand up and pay you a fair price more than you asked.
Seller should stick by his deal but buyer should at least feel some remorse for taking candy from a baby.

Seeking Knowledge and a Good Deal.
Always looking for neon signs and skins , Flying A ,& Wayne 60s.