Recover from Polio: $30
In the United States, polio is a disease from the days of yore, long since eradicated. But in Africa and South Asia, while vaccination programs lead by the WHO have lead to a decline in new outbreaks, many people are still suffering from its effects.
30-year-old physiotherapist Sanjay Kumar has developed a low-cost treatment for helping paralyzed survivors regain their mobility; the process takes one to two months and costs about $30-$35 per patient. Patients are given plaster casts, which are cut and replaced weekly, using wooden wedges to straighten the muscles.
An infrequently-updated blog about the work is available here.