Categories and user-submitting

Hi,

I’m working on a site where users can sell and buy businesses. This means that a user submits a business (description and such) and then others can contact this person and a deal might take place.

Problem: When the user submits, I need them to be able to pick a “Business category” and a “Location”, from which buyers can filter all the posts when searching.

So I’m looking for a plugin, or a trick, or something, where people can pick their location from one dropdown, and their category from another – and these two will then be visible when looking at the post. And searchable via filtering.

Sorry if this is a very open question, but I’ve been googling for an hour without finding something that can help me with this. I might be searching for the wrong terms or something.

Thanks in advance

-Amy