Buy. Share. Sell. Print.
What's a 3D printing marketplace? In generic terms, it's a place where people can buy, sell, or share anything related to the 3D printing industry. But there are a wide variety of 3D printing marketplaces out there, each with a different menu of services.
Thingiverse: A site to share and download free 3D files designed to be printed on your own 3D printer at home; a product of Makerbot, one of the largest manufacturers of personal 3D printers (now a subsidiary of Stratasys, the industry leader in professional 3D printers)
Cubify: Free sharing of 3D files, similar to Thingiverse; a product of Cube, one of the other big manufacturers of personal 3D printers
Threeding & Sculpteo & 3DLT & CGTrader & Pinshape & 3DPrintWise: Sites for free and paid 3D-printable files; they often provide services that integrate the 3D files for use with a variety of 3D printers and modeling/rendering software
LayerByLayer: Similar to the sites listed directly above, but #1 difference from competing marketplaces is their "we sell ready-to-go prints, not files" approach; everything you download comes pre-sliced for your printer, so you don't need to mess with files, print settings, or slicers
Physibles: Dedicated to the free sharing of 3D-printable files (a service of ThePirateBay, a well-known torrent database)
3D Printing & Manufacturing Services
Shapeways & i.Materialise: Provide on-demand manufacturing of 3D-printed objects; designers and artists upload their files and offer them for sale to the general public; can print in many materials, including plastic, steel, precious metal, ceramic, and sandstone
Ponoko: Another on-demand 3D printing manufacturer, similar to Shapeways and i.Materialise; big difference is their use of a distributed network of manufacturers to fulfill orders
Kraftwurx: Offers on-demand 3D printing in 85 different materials with 126 manufacturing facilities worldwide; also offers the Digital Factory, a one-stop shop for starting and running a 3D printing store on the web—handling checkout, production, and delivery to clients (uses geo-located factories for local manufacturing)
Are there any 3D printing marketplaces you know that aren't included on this list? Tell us in the comments below.