[RC-Monster Mike]

We used to offer lower cost shipping methods - the problem was everyone selected the lowest cost option, but if the package got lost, they simply dispute the charge through paypal or their credit card company. Even after some folks "accept the risk of a low cost shipping method", some have disputed their purchase. Since these low cost shipping methods don't offer tracking, we can't prove delivery and end up losing the goods and the money. We lost several thousand dollars in the first few years and changed our shipping methods to protect ourselves(we still get burned occasionally, but not on large orders, as they ONLY ship via Express or UPS). The USPS package pickup is free, Rene - this isn't a factor in the cost. They did raise the rates last year, but mostly it was always fairly expensive to ship via Express Mail. The packages can be tracked and delivery can be proven, which protects RC-Monster.
We often arrange smaller and far less expensive shipping methods for smaller orders with some email communication regarding the expectations. Cheap shipping is simply slower and less reliable. Great for the customer if the parts arrive, but bad for the business when they don't. :)