You will need to consult the catalogs and do some research. Most libraries will have a copy of Scott's Postage Stamp Catalog of the World. Air Mail stamps will be found in the back section of the appropriate country.
First of all, you have to identify the specific stamp or card. That in itself can be a daunting task, but most of the catalogs are well illustrated with lots of information. Once you know what item you have, the catalog will provide a set of prices that can be used to estimate value.
Type your answer here... Can I use a 55 cent Alice Hamilton stamp to mail a letter todayi?
Air mail stamps are good for ordinary postage- your stamp is still worth 7 cents if unused.
About eight cents, so you might need a couple more to mail something.
Put a 42 cent stamp on it. - Stuart
20 cents.
will a .46 cent stamp mail a 1.1oz letter?
It currently costs 44 cent to mail a regular envelope, which is the price for a stamp.
The most common G rate stamps sold for 32 cents and are still worth that amount as postage. There was also a make-up rate stamp worth 3 cents that was intended to be used with a 29 cent stamp to reach the new G rate of 32. There was also a G rate stamp for post cards, worth 20 cents and one for non-profit presort use, worth 5 cents.
1, so long as it is a 48 cent stamp assuming you are in the United States
Without a great deal more information an answer cannot be provided. Consult a catalog on line or in your local library, that will help you identify the stamp and its value.
All U.S. stamps since the Civil War can still be used to mail letters and packages. So a 4 cent stamp is worth 4 cents today. If the stamp is old you can check in the catalogs to determine collector value. Few stamps issued since 1950 have significant collector value.
USPO stamp rates are higher in 2014. To mail a letter to Arizona from Michigan costs one 48 cent stamp.