I have a lot of stamps but these seem to stand out as valuable.
The green one is a $1.00 U.S. R173 Internal Revenue Stamp from the late 1800's. I think it is an R173 Scott number.
The State of California 57744A Tax Stamp is from the 1930's.
I also have a group of 1922 - 1932 four State of New York Stack Transfer Tax including $1, $2, and $4.00
The main photo is a popular group of 6 State of California two Oz. tax stamps.
Finally, the sale will include three Documentary Stock Transfer Stamps including an RD11 green, RD13 red, and RD16 blue Stamps (Blue is not in photos because I ran out of space)
If your interested in other stamps I own, let me know. I don't think there are expensive stamps in the collection however many of the international stamps are very nice.
Product code: Nineteen United States Delivery, Tax and popular Documentary Stamps