I can ship the same example item by Priority Mail for only $3.85. But UPS wants $6.00 and they SUCK !!!! I personally will NOT buy from an eBay seller that ships by UPS.
The Postal service is only cheaper upto 2 lbs and if you ship with any shipper for long they WILL mess up some of your packages. I can ship a 10lb package to CA for $9.00 or $10.00 via ups or fedex the same package would cost $19.30 via priority mail. Also both ups and fedex offer $100.00 of insurance for free so if something does go wrong you are covered. I ship with the postal service as well as Fedex ground so I know the good and bad of both.