Used

Arcadium
Offers games, systems, and accessories for Atari, Nintendo, and handhelds such as Game Gear.
http://myarcadium.tripod.com/

The Goat Store
Retro video games to purchase, as well as editorials, the history of each console sold and new developments for classic systems.
http://www.goatstore.com/

J2 Games
Sells classic video game hardware, games, and accessories.
http://www.j2games.com/

JJ Games, LLC
Specializing in used video games and accessories for a wide variety of systems. Includes how-to articles.
http://www.jjgames.com/

Video Games Plus.net
Offers used video games, systems, and accessories for Sony, Sega, and Nintendo.
http://www.videogamesplus.net/

Warpzone Video Games
Sells console hardware and games for a variety of systems.
http://www.warpzonevideogames.com/