FedEx or USPS Parcel Post for big boxes, I'll use either depending on the value of the package and if insurance is deemed neccesary. for small packages I almost always use USPS exclusively.

I never use ebays price calculator, I like to use flat rate boxes or small boxes via Parcel Post.

When calculating shipping I use one flat rate based on Tampa to Seattle, if I end up shipping something for considerably less I'll refund most of the difference.