Smart prosthetic arms are going to be much more affordable in the future. Take the HACKberry for instance: it is a myoelectric prosthetic arm created by exiii that makes this technology accessible to more people. This open source prosthesis uses a smartphone to process data. The hand detects when nerve and muscle tissue is stimulated by signals from your brain and send the data to a smartphone to translate it into hand and arm movements.
HACKberry happens to be a 3D printed bionic arm. That means broken parts can be easily replaced. You can find out more information here.