The shipping charge calculation seems to be a major bug on this platform. I am in the process of constructing a “flat-rate” table that should approximate average shipping to different parts of the country. As I monitor shipping costs, I will update as seems appropriate. In the meantime, please rest assured that we do not want to charge you too much for shipping!
Moreover, we do not want to have to subscribe to a costly service that would perform what should be one of the most basic e-commerce functions in existence. Doing this would raise the cost for everyone, and we want to avoid that.