If you ship in bulk, UPS gives major discounts (50%+ in some cases). Companies sometimes also take a loss on shipping, but make it up in profit from the sale.
seller is an idiot.USPS is always cheaper than UPS. But no, you can t ship roller blades for $6 even with USPS, especially when you don t even know who is buying them and where the they are shipping to.FYI - UPS provides more services (automatic insurance, easier tracking, etc).
