3d hubs is a service based on people with printers in your area. They have decided to let outsiders submit files to be printed on their equipment. Each 'hub' decides what is cost effective for them, based on time and materials. Without knowing somebody personally with a printer, a hub quote is about as cheap as you can find. As for the shapeways quote, you can request various materials I believe.

Shapeways is not cheap, but you almost always get good results. Hubs can be hit or miss.

If you want quality, you usually have to pay for it.