Here is a sample auto repair site, it is a composite of of various other ones. This business however is completely fictitious. However the domain name gets about 300 hits a month because it was once a real business

This is the manager backend that drives the used vehicle listings, as well has a simple system to store contacts and offers for the site above.
You can easily add a vehicle listing, change it, delete it or just set it to not show.You can also store sales leads and contact them via phone or email. Of course on your site, these backend pages, the whole /manager directory, would be protected by a username-password prompt

Of course, you can't alter data or delete pictures, to avoid e-vandalism. But as the owner, you can alter it yourself.