Michael said:

We had banks during the 19th century, and no long term inflation. A dollar in 1800 bought the same amount of goods as a dollar in 1900. It wasn't until the fed was authorized early in the 20th century that we had that we wound up with non stop inflation. It takes 98 dollars to buy what a dollar bought in 1900.

The Hershey 5 cent bar was invented by Hershey himself, and produced (in an effort to maintain his legacy of the nickle bar) from 1921 until 1968 when they company could no longer produce the bar for a nickle. Note the depression era deflation.

1908.....9/16 oz.....2 cents

1918.....16/16 oz.....3 cents

1920.....9/16 oz.....3 cents

1921.....1 oz.....5 cents

1924.....1 3/8 oz.....5 cents

1930.....2 oz.....5 cents

1933.....1 7/8 oz.....5 cents

1936.....1 1/2 oz.....5 cents

1937.....1 5/8 oz.....5 cents

1938.....1 3/8 oz.....5 cents

1939.....1 5/8 oz.....5 cents

1941.....1 1/4 oz.....5 cents

1944.....1 5/8 oz.....5 cents

1946.....1 1/2 oz.....5 cents

1947.....1 oz.....5 cents

1950.....1 oz.....5 cents

1954.....7/8 oz.....5 cents

1955.....1 oz.....5 cents

1958.....7/8 oz.....5 cents

1963.....7/8 oz......5 cents

1965.....1 oz.....5 cents

1966.....7/8 oz.....5 cents

1968.....3/4 oz.....5 cents

1969.....1 1/2 oz.....10 cents

1970.....1 3/8 oz.....10 cents

1973.....1.26 oz......10 cents

1974.....1.4 oz.....15 cents

1976.....1.2 oz.....15 cents

1977.....1.2 oz......20 cents

1978.....1.2 oz.....25 cents

1980.....1.05 oz.....25 cents

1982.....1.45 oz.....30 cents

1983.....1.45 oz.....35 cents

1986.....1.45 oz.....40 cents

1986.....1.65 oz.....40 cents

I cleaned up the units, and made a nice little graph in excel. Edit- note, that's not dollars, but rather cents... my bad on the series name. :