C'mon, really why is everyone giving Atomicboy a hard time?
Yes, we all know that many Pinsiders don't like "auction" or "fishing" posts, but he has said he won't take offers less than $6K - so you can't be too butthurt if he does not respond positively to your $1,800 offer.
So if the game is not worth at least $6k to you, then drain the post, or check back in a few weeks if you are curious about the outcome.
I would NEVER sell a game on eBay, that is terrible advice.
Between their 16% cut and the probability of a Paypal chargeback, you would have to be an idiot to sell an item that expensive on eBay.
Even if a eBay sale nets you an extra $1000, that extra money won't matter a bit when the buyer claims it's counterfeit and you don't get your money or game back.