In 1960, a postage stamp cost 4 cents. This rate lasted until 1963, when the price of a postage stamp was raised to 5 cents. The 4-cent postage stamp could be used to mail a letter weighing 1 ounce or less within the United States.
Postage in 1960 did not vary based on the shape of the letter. However, in 1975 the U.S. Postal Service introduced different postage rates for differently shaped letters. As of 2014, postage for letters costs less than postage for large envelopes of the same weight. In 1960, letters could be mailed with a 4-cent stamp regardless of shape. Postcards were an exception, since they could be mailed with a 3-cent stamp.