Just be aware you will be less likely to be able to move it here and recoup what you spent either way it goes, trade or sell wise, if its a new sealed copy. Not many here do the sealed game bit, just a few here and there, so you really would be better off taking it to ebay if you plan to break even or rake in a profit. Be aware also, for what its worth, you'll make more friends then enemies here BY NOT advertising about doing this kind of stuff. No one here really cares much to help the ebay resell market, nor people who are relatively new here and partake in that activity. It will create a bit of distrust on your end, because people sell games lower then ebay prices often here and cut other members deals. People will second guess giving a guy a deal if they know hes the one buying stuff and taking it straight to ebay for profit.
If you want to know what a game sells for on there, go check completed auctions and keep it to yourself. What it will sell for on there is going to vary from what it will sell for here for obvious reasons everyone's tired of repeating ad nauseam.