Buy quality game art and tile sets. This site often offers free sprites and tilesets for use in your games.
Free Graphics for Flash and Indie Games
Free sprites, textures, and tile sets for indie game developers.
A resource for creating your own games. You can download Gamemaker 7, which allows you to make your own 2 dimensional video games, find game sound and graphic downloads, participate in the game maker community forum, as well as play games on the site.
OpenGameArt.org provides a variety of high quality, freely licensed art, so that free/open source game developers can use it in their games.
Game assets for indie game developers.