The Seven-cent Prexie
Fourth Class use
The fourth class special book rate was three cents per pound From July 1, 1942 until January 1, 1949. A one cent surcharge with a one cent minimum was in effect from March 26, 1944 until January 1, 1949.
This package would have weighed between one and two pounds. A one cent surcharge would have brought the postage to seven cents.