MarketPress and USPS shipping

Hi, We are currently using WP E-Commerece from but it keeps having errors on our site. We are considering changing over to MarketPress, as it looks like a good fit. My only worry is that the shipping modules aren't already integrated into the system. I notice in the documentation you say it is fairly easy for a developer to do. Im not the most experience coder, so I am hoping that there is someone out there who has already set MarketPress up to work with USPS. We also have a UPS account, if someone has managed to figure that out. At this point we will pretty much take anything... Our store has been down for 2 weeks because of delays and errors with the current setup. Not to mention it was only open for one day before all this garbage.

Thanks in advance!
Rob Webmaster