Ad management theme

Hi,

My question is about some advice.
I am looking for a theme that will allow me not only to place ads, but also that will allow visitors to submit requests to post ads, on several spaces of the theme (Header, widget area, footer, etc).

As an example, say I have a site that promotes a certain product, and I were to sell ad space on it to which I would only have to approve the ad and say where it would be posted.

Come to think of it, maybe it’s more of a combination of theme+plugin.
Can someone suggest a good option that allows that?
Oh, both banner ads and text ads.

I appreciate all who answer and the wordpress community for their help.

Thanks.
JL