The first postage stamp, the One Penny Black, was issued by Britain in 1840. It pictured a young Queen Victoria, was produced without perforations (imperforate), and consequently had to be cut from the sheet with scissors in order to be used. While unused examples of the "Penny Black" are quite scarce, used examples are common, and may be purchased for $25 to $150, depending upon condition.
Children and teenagers were early collectors of stamps in the 1860s and 1870s. Many adults dismissed it as a childish pursuit.
It was not until the 1920s that publicity about valuable stamps encouraged a large increase in the number of stamp collectors. This rapid increase in postage stamp values was largely due to very few of the older stamps being saved in good condition. Especially difficult to find were pairs, triples, and large blocks of older stamps.
Because many U.S. stamp issues of the 1920s rose rapidly in value, during the 1930s many American collectors stockpiled mint U.S. stamps with the hopes of selling them for a sizeable profit in a few years' time. This never materialized. Even today, more than 60 years later, one can find many 1930s U.S. issues in mint condition for close to face value, and many stamp dealers and collectors still use stamps issued as far back as the 1930s for postage when mailing letters.
Most U.S. postage stamps issued since the 1930s are easy to obtain and have minimal value. Some high face value stamps, such as the $2.60 United States Graf Zeppelin issued in 1930, are worth substantial amounts of money. Other stamps issued since 1930 that are usually worth something are souvenir sheets from popular countries, hard to find plate number coils, and errors in printing.