The primary costs are in the machine itself and in the consumables or injection materials as most of the cheaper machines are limited to plastic, but many will function with more than one type of plastic.
Furthermore, 3D printing even has the potential to change the drug landscape. Researchers at the University of Glasgow have developed a system that would print the necessary lab equipment to create pharmaceuticals. While this kind of technology has the potential to democratize the millionaire pharmaceutical industry, it might also enable people to print illegal narcotics from home. It also means that the drugs people buy could become more dangerous than they are now.
As with any cultural postulations about the future, the idea of bio-printing extra body parts can sound ridiculous but this is not as far fetched. As robotics and automation increases over the years, people may want specific augmentations that will enable them to perform certain unique tasks... again this may have severe implications in many areas... imagine what this can do to the military sector.