There's a lot of talk about 3d printing, and with good reason, there is a lot of potential in the technology.
The Replicator from Makerbot seems like a good place to start for desktop manufacturing. They have some software that takes .stl files from your favourite CAD program and turns them into slices for printing.
The filament needed for printing is quite expensive, around $48 per kilo, so a 100g model will cost nearly $5 to make, just in materials. The Filabot is a desktop recycler to turn waste plastic into filament for use in your 3d printer.