Originally Posted by Myth
I understand where the guy was coming from but I also understand that it was a good deal in the first place and you didn't mean to scam him. Tell him that you were not aware that the drive was broken and you'd take it back and give him his money. He probably will turn you down because he knows he got a good deal with or without the drive. If he does want a full refund, you could always re-sell it to somebody else for $250, so I wouldn't just give him $50.
DO this. He most likely will shut up and take the good deal he got.