For stamp collectors, determining the value of a stamp collection is crucial. A price guide can help you determine whether an item is worth its price. Most buyers treat stamps as artifacts, and choose them based on their quality and condition. There are two primary ways to appraise the value of a stamp: by inspecting a catalogue number or by looking it up in a database.

If you're just starting out, it's best to consult a professional to get an accurate price on the stamps you're considering purchasing. Most stamp catalogues and publications assign optimistic values to stamps, which are not necessarily correct. Most dealers discount their prices from these displayed values. Online auction sites also often show credentials from the ASDA and the NSDA, which convey a dealer's quality and standby. These credentials become even more important as the price of an item increases.

A stamp catalogue is the primary tool for serious collectors, and it's the best reference for determining the value of your collection. Most stamp shops sell stamp catalogues, and some are available online. Some of them are free while others have a fee to access them. There are hundreds of stamp catalogues, and some specialize in a particular country or period. There are also stamp collector clubs, which usually provide their members with a free copy of the catalog.