All orders are made through the Shapeway.com website. Most of the models are produced in their Long Island City, New York factory on machines that cost between $80,000 and $250,000. That's a bit more than I can spend on a 3D printer.
When you click on a model, or a category of models, you are taken to my shop on the Shapeways website. They process the order, take the payment, and ship it to you.
While you are there take a look at items that other designers are offering. Shaeways will mix and match your order between models offered by multiple designers.
The biggest caution I offer is be a little more careful of models offered by a designer who does not include actual pictures of at least some of his models. Some people offer models for sale that have not been tested, and are unprintable.
I try to test all my models. If I haven't, I offer that information to my customers.