Sometimes [link|http://www.computergeeks.com|Computer Geeks] has Playstation and N64 games on sale. They usually have a ton of them, but right now all they have is the N64 Boxing game for $10USD. Look under consumer electronics. They do have a $120USD Dreamcast software and 1 controller bundle.

Since the Gamecube is coming out, look for KBToys, Toys R Us, K-Mart, and others to discount the N64 games to make room for the XBox/PS2/Gamecube games.

If you can see if there is an Babbages or [link|http://www.funcoland.com|Funcoland] near you. They buy/sell/trade games. Also visit [link|http://www.gametraderinc.com/|Game Trader Inc] they usually sell N64 and other games that have been previously used.