It's not really surprising that a lot of Xbox One owners are taking advantage of its supply shortage to make a quick buck through eBay. In fact, this has happened with almost all previous console launches; however, it seems that Xbox One owners are finding new ways to monetize their consoles without losing them.
By the time of writing, around 200 auctions are available on eBay selling Xbox One day one achievement codes. When entered into Xbox LIVE, this one-time code earns its user an achievement for being a day one Xbox One owner. Apparently, the street price for those bragging rights is around 30 bucks (or upward of $60 if you opt for the "buy now" option).