Take a guess how much money is in your wallet right now. It might be enough to save a child from measles or polio.
You could buy one vaccine for the same price as:
a) A quarter-pounder with cheese meal at McDonalds
b) A tank of gas
c) The sandals in your Zappos shopping cart
d) The amount of money you spent finding the perfect nail polish color (i.e. many bottles)
If you guessed the fast food meal, you win. A mere $5 per vaccine. Five dollars. Four diseases for $20. That's a large pizza with olives, mushrooms and onions delivered to my doorstep with a generous tip.