If you are certain that it is from 1919, then it must be Scott Catalogue number OX21. The catalogue value is $0.20. That is the minimum value for any stamp listed. Therefore, the true market value for the stamp is very small - maybe around $0.05-0.10.
A stamp is worth more unused
unused
33 cents if unused.
About 25 cents
Thirty-two cents.
If this stamp is in good condition - well centered, no missing parts, full gum if unused and lightly canceled if used, it retails for about $9 unused and $.20 used.
The Post Office. Stamp Collectors. Stamp Dealers.
Stamps in the US can always be used at face value. The post office won't buy them back, they will tell you to use them.
50 cents if unused. Nothing if used.This must be the most common US airmail stamp.
Not much maybe $1 or $3 at the most.
Unused, you can use it for 14 cents postage.
Yes. As long as the stamp was issued after 1867 and is still unused, it doesn't matter the denomination. It is still postage.