The “Jaipur foot” (also known as the “Jaipur leg”) – is an effective and easy-to-fit prosthetic lower limb that can be produced for a little as $30 and is provided for free by the charity Jaipurfoot.org. The prosthetic was first developed in the 1960s by an orthopedic surgeon and a sculptor. Since then the charity has provided over 300,000 limbs in 22 countries. You can read more about this organization and their work in this Time magazine article.