Good luck with your business idea, but you're not exactly the first person to think of this. Are you already an expert at 3D modeling, with a lot of designs you think will sell briskly? Or was your plan to find models on Thingiverse, print them out, and try to sell them?

Yes, printers capable of printing directly in metals cost a lot more than ones that print in plastics. On the order of a thousand times more. If you buy the cheapest printer available, you're likely to come up with cheap-looking prints. The same goes for filaments. There are lots of kinds available, and their costs vary a lot. If surface detail is important to you, then plastic extrusion printers might not be what you want to use; even the best of them will produce parts with noticeable striation. I'd suggest you create (or find) a design you think you can sell, and use a service like 3DHubs or Shapeways to produce some on a range of machines, so you can see the differences close-up and test out the design to see if it really works, how much you can realistically sell it for, and use that research to guide your choice of a printer, if you decide this idea is feasible.

Andrew Werby
www.computersculpture.com