That is Scott Number 1721. It has a minimal value and can be purchased for about 20 cents.
$1 try ebay
Without knowing what the particular stamp is and it's condition, it is impossible to value. There was more than one stamp issued during WW2.
The tulip stamp was marked as the F Flower stamp. It has a face value of 29 cents.
The greatest value at all - peace.
It is a forever stamp. It is good for the current value of a first class stamp.
The value of a Top Value Stamp, "Toppie," the elephant sign is approximately $42. The better the condition of the stamp, the more money it will be worth.
Face value of the original stamp was $0.20
The stamp-postage value of a stamp is visible on the front of the stamp.
The value of the 1910 1955 penny stamp value is one pound.
3 cents.
That is Scott number US 1721. It has a 75 value new and 15 cents used.