UPS definitely charges different rates for different areas (and even the USPS does somewhat once you get to parcels) but most companies hide this from the buyer to make things simple (even so far as dropping to "free shipping").
Smaller companies often don't want to take a hit on the non-contiguous - but depending on what you're buying the places that DO charge shipping may actually be the cheapest overall.
The fun really comes when you have places in the USA that the post office doesn't even deliver to (in very VERY rural areas, every address is actually a PO Box; you have to drive into town to get the mail and that can be many, many miles). Often UPS and FedEx will think they can deliver, and then determine they can't. Fun times.
Smaller companies often don't want to take a hit on the non-contiguous - but depending on what you're buying the places that DO charge shipping may actually be the cheapest overall.
The fun really comes when you have places in the USA that the post office doesn't even deliver to (in very VERY rural areas, every address is actually a PO Box; you have to drive into town to get the mail and that can be many, many miles). Often UPS and FedEx will think they can deliver, and then determine they can't. Fun times.