Looking for the fitting classifieds plugin

Hi, I’m having problems with finding a fitting plugin for my site.
I have built a site similar to craigslist. but I would like to find a plugin that will allow me to putt a category into a certain page that I have built.
For example, I have built multiple pages on my classifieds page and I would like to have people post their ads by just selecting that page and not having to select a category.
Say I have a car parts page, I would like for users to post only on that page with out looking for a correct category. is it possible?
Or do I need to work on creating my own plugin?

Also I have looked at a few classifieds plugins and was unable to find one that has these functions.

Any suggestions and help would be greatly appreciated.
My web page is http://www.evohive.com
Thank you!!!