Ebay you'll be scammed. Buyers will claim it's damaged and Ebay always sides with buyers, so you'll lose the money and the game (they don't have to return it).
Facebook/craigslist you'll probably be robbed or killed unless you meet up at a police station.
That leaves pawn shop, who will probably try to rip you off.
The only 99% guaranteed safe option is to find a gaming community with its own feedback system that will hopefully protect a sale.
Your loyalty lies on the wrong side of the future