Catalogs online are usually not a scam. Check the company that is offering the catalog. Usually these are there to sell you stamps. When valuing stamps remember a couple of key things:
Consult a postage stamp catalog. Scott's is the main one in the US. And a quick look through a dealer catalog, Mystic has a good online one, can be a big help.
First determine the condition. Information on how to do that can be found in a stamp catalog online or in your local library. Then identify the stamp. That will allow you to provide the proper condition rating.
You can consult a stamp dealer in your area. A knowledgeable collector can probably help you with their references. You can also do it yourself with a stamp catalog either online or at your library.
Most libraries have a copy in their reference section. You can usually order them online from Scott's, or you can get them through a bookstore. Some stamp dealers carry them as well.
It will depend a great deal on how old it is. For a modern stamp, you can probably buy one for around 20 cents, but you would have difficulty finding someone to buy it from you. If it is from an earlier age, you can consult a stamp catalog, online or in your library, to identify and find a catalog value.
There are some online stamp catalogs available. I often use the one by Mystic Stamps. They have put their paper catalog online and it includes information on how to determine condition. The values...
There are some online stamp catalogs available. I often use the one by Mystic Stamps. They have put their paper catalog online and it includes information on how to determine condition. The values provide are those at which they are willing to sell the stamp. Buying will be a fraction of that value.
Find it in a catalog. The entry will typically include the date of issue, as well as the catalog value of the stamp in mint and used condition.
First you need to specified to country, the series, and the conditions of the stamp, and if it has ever been used or not. Consult an online catalog, or hard copy at your local library.
There are a couple dozen of them. Once place to look would by the Mystic stamp catalog, available online. Or a copy of Scott's catalog, usually available in your local library.
It is called a catalog. In the US, Scotts Postage Stamp Catalog is most popular.
There are several sites online that can be a big help. Look for "stamp identifier" using a search engine. You can type in the part of a word that you can read and it will help. They usually have lots of pictures to help with symbols and names.