Prices go up. Occasionally, prices go down. But for 70 years, the price of a bottle of Coca-Cola didn't change. From 1886 until the late 1950s, a bottle of coke cost just a nickel.On today's show, we find out why. The answer includes a half a million vending machines, a 7.5 cent coin, and a company president who just wanted to get a couple of lawyers out of his office.This episode originally ran in 2012.This episode was hosted by David Kestenbaum. Alex Goldmark is Planet Money's executive producer.Help support Planet Money and get bonus episodes by subscribing to Planet Money+ in Apple Podcasts or at plus.npr.org/planetmoney.