What your "friend" did is inexcusable. It's something a 10 year old does to another 10 year old and as a parent if my kid did it I would force him to return it to you "gratis" and apologize. He would lose the $80 and hopefully learn a lesson on how you treat people.
When an adult does this, it says to me he is a pr!#k. He is not your friend. If I had an ebay account I would bid $250 and raise it if need be(hint to anyone who has a fleabay account they can burn). I might even report the unit stolen and tell the police you found it listed on Ebay. He is not your friend so don't worry about burning bridges.