How much did stamps cost in the 1930's?

Answer 1

Postage stamps always cost the face value of the stamp and various stamp values existed then just as they do today, but first class postage for a typical letter was 3 cents during most of the 1930s

Answer 2

The US domestic rate for an ordinary 1st-class letter went up to 3 cents on July 6, 1932.
It was 2 cents when the 1930's began and stayed at 3 cents until 1958.