ZenCart Shipping Module Enhancement

I chose Script Installation because there isn't a ZenCart project. If there is a script available for what I'm looking for, I'm happy to use that script. I've priced the project up to $250. I'm running the following: Zen Cart 1.3.8a Database Patch Level: 1.3.8 v1.3.8 [2008-05-26 07:20:51] (Fresh Installation) v1.3.8 [2008-05-26 07:20:51] (Fresh Installation) PHP Version 5.1.6 I can currently offer free shipping but only "Always Free Shipping". What I need to be able to do is offer only free shipping to the US, via first class, with Priority & Express available at the standard rates. Additionally, I want to offer International 1st class at no charge but charge standard rates for International Priority & Express. Is it possible? Can you make it happen? Looking for qualified ZenCart Guru :) Thanks so much!