How much is an American pan American 1901 stamp worth?

Answer 1

The US Post Office didn't issue any new stamps in 1905. You must have an older stamp with a 1905 cancel on it. Without knowing which stamp it's not possible to offer more info. You need to include colour of stamp, who or what is on it, condition.

Answer 2

You will need to consult the catalogs to identify the specific Pan American stamp you have. Most libraries will have a copy of Scott's Postage Stamp Catalog of the World. 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.