There are several places you can go on Yahoo! to purchase car parts and accessories:
Yahoo! Classifieds has a section for auto parts in the General Merchandise section.
Yahoo! Auctions also has a section for auto parts that may be useful.
Many stores in Yahoo! Shopping sell auto parts, accessories, and services -- everything from hub caps to roadside assistance to Harley Davidson apparel. To visit automotive stores in Yahoo! Shopping, go to the Yahoo! Autos home page and click on the Automotive Shopping link.