Solution:
Users can [post their car by choosing some membership plans. According to this the number of cars he can post and number of days the posting exists will change. Buyers can search using their Zip code and other criteria. Users can post their ad banners in any page. The display of the banner depends on the package they have selected.
Administrator can manage all the top banner links. He can add sponsored links also. Administrator approves the ad banner requests for each page. The back ground color and the color of menus can be changed from admin. A Google ad sense is incorporated in the home page of the site.