via: http://www.ameshistory.org/exhibits/events/rationing.htm

When the USA entered the war, the economy switched over to an emphasis on military production with consumer goods a low priority. The U.S. Office of Price Administration (OPA) froze prices on most everyday goods  (e.g., gasoline, tires, sugar, meat, silk, shoes, nylon). In May 1942, war ration books and tokens were issued to each family, prescribing the amount an individual could purchase.

Read this interesting post: Rationing on the US Homefront during WW II.