In the 1930s the price of gas averaged about 10 cents a gallon. A penny was a lot of money, especially during the Great Depression for people out of work. Even before that, at least as far back at 1914 there was a Texaco gas station in Texas that sold gas in fractions of a cent at 14.5 cents a gallon while his competition was selling it at 15 cents. In 1932 the government introduced a one-cent federal excise tax on gasoline. Competition being what it was, it caused many retailers who were selling gas at, say, .09, to go to .099. Then in 1933 the excise tax rose to 1.5 cents, and the fractions of a cent became the norm, with 9/10 of a penny quickly becoming commonplace.