I don't know, but try a site like www.ValueJockey.com. There, you can ask questions about how much stuff is worth.
The value of an Anna Julia Cooper postage stamp would depend on various factors such as its condition, rarity, and demand among collectors. On average, a mint condition Anna Julia Cooper stamp could be worth anywhere from a few dollars to potentially over $20.
Forever
The current value for a standard postage stamp is 46 cents.
In used condition it is not worth anything. In mint condition it is probably worth 2 times the face value.
The F series stamps were issued in 1991. The postage stamp has a face value of 29 cents.
The value of a 100 Jackie Robinson postage stamp can vary based on its condition, rarity, and demand among collectors. Generally, if the stamp is in mint condition and part of a limited edition, it could be worth more than its face value. However, for standard used stamps, the value may be close to face value, around $100. To get an accurate appraisal, it's best to consult a stamp collector or a professional appraiser.
That would be US Scott Number 2097 It has a minimal value of 20 cents used and $1.50 in mint condition.
Face value of the original stamp was $0.20
This would depend on what year it was issued and the condition of the stamp. For example a used stamp in average condition from 1998 is worth between 6 and 19 cents to a collector but could not be used for postage. An unused stamp in average condition from 1998 would be worth face value; in the case of a forever stamp (without a face value printed), it would be worth whatever the current postage rate has been raised too (as of January 2013, it would be worth 46 cents) and could be used for postage at that value.
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 stamp-postage value of a stamp is visible on the front of the stamp.
The face value of the D stamp was 22 cents when issued in 1985.