Where do you go for used Gamecube games?

I want to fill out my collection with some Gamecube games but they are damn near impossible to find. I checked every Gamestop in my town. They have one little shelf with maybe 15 games in the whole store. For some reason there's wall to wall PS2 games though. I know the Gamecube had probably 300 or so games. I don't understand why they are so hard to find.

http://www.nintendolife.com/forums/retro/where_do_you_go_for_used_gamecube_games

I thought that topic answered your question? You can order GameCube games from the official GameStop site, or even try out Ebay or even Amazon.

there's a big flea market here that has em! but you can only go there on weekends :-(