Create Meta Titles code or addon for classifieds script.

Greetings, I have setup a new classifieds site. most of the classifieds site is SEO friendly and uses meta titles and descriptions, with the exception of all states/cities which uses the exact same title from the classifieds script, this is duplicate content. I am looking for someone to create easy to install code that will never interfere with the operation of the script or upgrades. I can set the meta tags manually, but I need the process in place to the point where I can edit each section ie: state/city/category, etc... 1: I need meta titles for each step. Home Page > Should use its own meta title only ie: > Alabama > Birmingham, AL > Auto Parts forsale in Birmingham, AL So I need to be able to add a meta title for all countries, states, cities, and categories, needs to be easy, and simple to install or remove. I am looking for a low cost solution to make this happen. Please post reply for website. Thank-You ps. a simple solution is to create what code you need and use tags that I can insert ie: %country% / %State% / %city% / add title manually so this way the script can use these tags to gather the info from the script regarding the country/state/cities, etc...does this make since?