Has it even crossed your mind that he just didn't WANT what you offered? Just because you offer me something worth $500 to SOMEBODY that doesn't mean it's worth that to ME. Plus I googled every combination of words from your quote I could figure and couldn't find the ad.
Either way, it's a crap rig, but he has every right to turn you down no matter what you offered him.
But even if you could get it for $100 it would sound like a hot mess.
So, I don't understand the controversy. He doesn't want what YOU have, And NOBODY can figure out why YOU want what HE has.