3-D printing can be expensive, but when compared to the typical cost of a prosthetic implant, it can be a simple, effective way to create homemade medical devices at a fraction of the price. Homemade 3-D printing for medical uses is what Paul McCarthy, the father of 12-year-old without fingers on his left hand, has done.

Leon McCarthy can now grab water bottles, pens, and utensils using his once-functionless left hand, which has turned into what he calls a special “cyborg” hand. McCarthy bought a $2,000 printer to complete his project, but the materials for the hand only cost about $10.

The design for the prosthetic hand, which was put up for free online, came from the collaboration of South African Richard Van As and Washington-based Ivan Owen. The pair connected after one of Owen’s videos of building a homemade mechanical hand went viral. Van As, a right-handed man who had lost four of his fingers on his right hand in a woodworking accident, connected with Owen with the hopes of developing a 3-D printed prosthetic for himself at home, as he wanted something inexpensive. After successfully working together on the project, they proceeded to collaborate on designing and building mechanical hands, or “Robohands,” for children born without fingers. The mechanical hand they developed for a 5-year-old named Liam cost less than $150, a marked difference from the typical $10,000 price tag for just one prosthetic finger.

3-D printers have grown to become more useful in the medical world, both among homemade, amateur designers and biomedical companies experimenting with new uses for the 3-D printing process. Back in March, a patient was able to have 75 percent of his skull restored with a 3-D printed implant. Engineers at Oxford Performance Materials in Connecticut created the 3-D skull after scanning the man’s skull and designing it precisely based on those scans. The skull was printed out layer by layer. Other companies like Organovo are able to create 3-D tissue models for research and drug applications, and aim to eventually create tissues for actual transplants. Researchers at the University of Michigan likewise created a 3-D printed tracheal splint for an infant born with tracheobronchomalacia, a condition of having weak windpipes, and sought approval from the Food and Drug Administration (FDA).

With the rise of 3-D printing use in medicine, the FDA will be stepping up its regulations of such devices. Currently, the FDA evaluates the 3-D printed biomedical objects the same way it does conventional medical devices. “We evaluate all devices, including any that utilize 3-D printing technology, for safety and effectiveness, and appropriate benefit and risk determination, regardless of the manufacturing technologies used,” FDA spokeswoman Susan Laine told LiveScience. “In some cases, we may require manufacturers to provide us with additional data, based on the complexity of the device.”