Sega, welcome to PCEFX. As others have mentioned, you are charging a tad high by about 5-10 bucks on some of your games. Typically on these forums, the community gives and gets deals that are better than Ebay. If you are looking for Ebay prices, many will suggest you take the games to Ebay.
Good luck with your sale (you will get sales if you consider coming down a little). =)