Geo-targeted ads on Front end

[fearmydesign]

I have a site where I want to display geo-targetted ads (by location another words). So if the person accessing the site from California, they see a different "Ad" on the front page, than someone logging in from any other "state" - At first I just want to have it display the ad by state, or by a radius location.

Anyways, hope someone has some experience with this. Please let me know time/cost etc via pm. Thanks