The only thing that's going to bring the price down on that high-tech prosthetic limb is wide-scale mass production. What's needed is a prosthetic limb craze. But the product itself has to prove its worth. If the limb is high-tech enough to be useful as, say, a third arm (rather than simply a replacement 2nd arm, which most of the public hardly needs!), that's when you have the crossover potential that could really make the market for it take off.
As with any cutting-edge novelty item, the first few cool kids in the pool are going to get soaked - they're going pay through the nose! But for them, that's part of the allure: being able to score and flaunt a high-tech gadget that's out of most peoples' reach. That's what starts the craze, and then it builds as others make sacrifices and/or wheedle the parents relentlessly for their own high-tech prosthetic arm, so they can be in with the cool crowd. As more and more me-too's start jumping on the bandwagon, the marketplace will respond. Different manufacturers will be one-upping each other to serve the demand with cooler features, and fashion color options.
As the craze really takes over, you'll see the price start to drop - demand will push production to the point where economies of scale kick in, and pretty soon, it will no longer be simply a status item. Finally we will begin to see a world where the dream of an affordable high-tech prosthetic arm for everyone is a reality.
This is what's needed. Creative solutions that take advantage of how capitalism can work for us.