These were issued January 11, 1926.
About 13 cents...
There is an 11 cent stamp in the presidential series which was current from 1939 to 1954. First class postage was never 11 cents-it jumped from 10 cent directly to 13 cents.
7.50
There was never a 12 cent stamp for regular postage. It went from 10 cents to 13 cents on 12/31/1975. There was however a postage card stamp for 12 cents in 1981.
It is worth $21
one cent
Most dealers are not going to be interested in buying a single stamp. You might try selling it on an auction site, but the postage cost will be more than the value of the stamp.
2 Dollars
You can sell a 13-cent stamp from 1978 through various platforms, such as online marketplaces like eBay or Etsy, where collectors often seek vintage stamps. Additionally, local stamp shops, flea markets, or antique stores may be interested in purchasing it. You could also consider joining philatelic clubs or forums where members buy, sell, or trade stamps.
I believe you mean the, Air Post Special Delivery (1934), 16 cents stamp, because there isn't a 10 cent stamp.There are 4 values for this stamp. This stamp is:Scott Catalog # CE1, (1934) 16 cent, Dark BlueThe values are:Catalog:New = 60 centsUsed =70 centsFace = 16 centsDealer value = 13 cents (20% below Face value)(Scott Specialized Catalog of US Stamps 2011, page 362)
That is Scott number US 1721. It has a 75 value new and 15 cents used.
Scott #1354. This stamp was issued in 1968. It was part of a ten stamp set printed on single sheets. A mint copy can be purchased online for $1. A used copy is 65 cents.