Here is a picture of the Iguanodon dinosaur stamp. It was issued in 1965 by the small republic of San Marino (located on the Italian peninsula). It had a value of 100 lire but the country now uses the euro as their currency. In 1965 it would be worth about 16 United States cents. The stamp was part of collection of nine issued that year.
The Iguanodon existed in the Late Jurassic Period (155-150 mya) to Late Cretaceous Period (100-66 mya). The fossil was named by Gideon Mantell in 1825.
San Marino is a very small country located inside of northern Italy. It is about 61 square kilometers in size with a population of about 30,000 people. One of their chief sources of income is tourism. They sell stamps and coins to tourists. More than likely these dinosaur stamps were part that income stream.
Sources:
http://en.wikipedia.org/wiki/San_marino
http://en.wikipedia.org/wiki/Economy_of_San_Marino
http://en.wikipedia.org/wiki/Iguanodon