The Audifans Marketplace is an excellent resource for locating and selling Audi automobiles and parts. Catering toward enthusiast of older generation Audi's, this is a valuable online resouce. Listings are free for sellers.

With hundreds of listings from across the world, eBay Motors has a huge selection of Audi's to select from. Registering with eBay Motors is requred and fees vary.

Not a classified listing, but Audi of America's own search engine for locating a Certified Pre-Owned vehicle in North America. Most North American dealers have their CPO inventories available from this search.

The AudiWorld classifieds offers a wide range of vehicles, parts and accessories. New listings are added consistantly, and there are categories available for non-automotive related items. Listings are free for seven days. Registration is required.

Fourtitude.com offers a free, forum based classified listings viewable across all of their partner websites. Registration is required to post your ad and new listings are added frequently.