http://en.wikipedia.org/wiki/Exonumia
Exonumia is the study of coin-like objects such as token coins and medals, and other items used in place of legal currency or for commemoration. This includes elongated coins, encased coins, souvenir medallions, tags, badges, counterstamped coins, wooden nickels and other similar items. It is related to numismatics proper (concerned with coins which have been legal tender), and many coin collectors are also exonumists.
Besides the above strict definition, others extend it to include non-coins which may or may not be legal tenders such as cheques, credit cards and similar paper. These can also be considered notaphily or scripophily.
The noun exonumia is derived from two classical roots: exo, meaning "out-of" in Greek, and nummus, meaning "coin" in Latin; thus, "out[side]-of-[the category]coins". Usually, the term "exonumia" is applied to these objects in the United States, while the equivalent British term is paranumismatica.
The words exonumist and exonumia were coined in July 1960 by Russell Rulau, a recognized authority and author on the subject, and accepted by Webster's dictionary in 1965.