THERE IS NO strict definition of a price below which a rapid prototyping or additive fabrication machine becomes a 3D printer. Some individuals include any machine that sells for below US$60,000, and others US$40,000. Considering that a large fraction of customers at present are in educational institutions, small companies or even single proprietorships and individuals, for whom price is of primary importance, we've decided to compile all the choices below about US$20,000. Here's what available today and its general qualities in the order of increasing price. To widen your choices beyond this, explore the commercial listings by technology. You can compare the specifications of the 3D printers listed on this page in our very complete chart.

Listings Color Key...
Hobbyist Kits & Do-It-Yourself	Commercially Available

Do-It-Yourself & Open-source 3D Printers Vendors of parts, kits and systems based on open-source hardware and software are sprouting like mushrooms after the rain. It is hoped they will not disappear quite as quickly. Nevertheless, if you wish to satisfy that deep-seated need for a 3D printer of your own, this is how to do it at minimum cost with maximum learning. Since much of the hardware is off-the-shelf, and some of it can even be made by the machines themselves, obsolescence or dead vendors shouldn't be major concerns. All systems have similar specifications and are thermoplastic extrusion-based, although materials capabilities may differ.
RepRap RepRap is short for replicating rapid-prototyper, an open-source 3D printer design project initiated by Adrian Bowyer at the University of Bath (UK). RepRap uses robotic thermoplastic extrusion similar to fused deposition modeling at present, but ceramic, metal and other materials may also be possible at some point. The ultimate intent of the project is to eventually produce a machine which can make copies of itself. Parts kits and individual items are now available from these sources. Darwin was the first version of the machine which has now morphed into Mendel, an improved version. Bits From Bytes (UK) Sells complete kits of mechanical parts for about US$630. RepRap: Store US vendor selling mostly parts and sub-system kits. Technology Education Concepts (TEC) US vendor selling Bits From Bytes kits to the educational marketplace in the US. A basic RapManUSA kits sell for US$1,495 and a fully-assembled version is US$2,395.
MakerBot Industries The CupCake is a small open source fused deposition modeling kit that's called the CupCake because its build envelope is about the size of a cupcake - a nice big one that would fit in a 4 inch cube. The US$750 kit comes with 5 lbs of ABS plastic. The company has set up an extensive framework of blogs, wikis, etc., and also a web-site reminiscent of Shapeways for users to exchange designs called the Thingiverse.
A1 Technologies Ltd. (UK) Offers the RapMan fused deposition modeling system kit for US$1,200 which is based on open-source hardware and software with much in common with the RepRap Darwin. Like that machine, it can print some of its own parts for replacement or maintenance purposes. A fully-assembled version, the RapMan PRO, is available for about US$3,300. Materials available include ABS, high- and low-density polyethylenes, polypropylene, polyvinylchloride and other plastics, with 500 gram spools of filament starting at about US$30.
Fab@Home An open-source project to design, develop and manufacture an inexpensive syringe-based additive fabrication machine and related software. The components to build the device can be had for as little as US$2,500, and a variety of materials can be used for building, from silicone to chocolate. The project is led from Cornell University, but there are participants from all over the world. A good choice for real pioneers and do-it-yourself fans who may be satisfied with parts and models that will not achieve a high level of precision, durability or speed of fabrication for some time to come. NextFab Store The company provides kits for fab@home machines priced in the range of US$3,100. It also sells major machine structural part kits for those wishing to procure their own electronic and mechanical components or to experiment. An (almost) completely assembled version of the machine can be purchased for about US$3,700. Automated Creation Technologies ACT provides a range of parts and assembled systems similar to and competitive with NextFab, above. In addition, a two head version of the machine is also available which allows for the possibility of using a support material during the build. Kraftmark The company sells epoxy- and polyether-based materials for use with fab@home machines. Also see their blog for examples and discussion.