I've seen a few gaming terrain listings available on Amazon. I've made several purchases from there, mostly for laser-cut MDF bases, in various sizes. I purchased some 3D printed mini's, once, I believe. Very satisfied with my purchases.
Went to a geek crafting convention, with some friends, two years ago. One of my group made some orders for 3D printed gaming accessories. He paid there, after seeing the samples on display. He then received them in the mail, some weeks later. He is very happy with his purchases.
I am all for small entrepreneurs making stuff with their Laser Cutter/Engravers, and their 3D printers, to sell to the public. That is what makes capitalism, great. I could buy a CO2 Laser Cutter/Engraver, as well as a 3D printer, but I just can't justify the investment of both time, and money, for the limited use I would get out of them. I will gladly pay someone for their products which I can use! I will spend far less than the cost of the Laser and Printer, and I will not spend many an hour learning the new tools… Cheers!