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 arcade tokens, badges, coin tokens, counter stamped coins, elongated coins, encased coins, medallions, military medals, souvenir medallions, tags, trade tokens, transit tokens, wooden nickels, and other similar items.
Some tokens were used for advertising, political purposes, exhibitions among other uses.
“Tokens” are often made of cheaper metals: copper, pewter, aluminum, brass and tin were commonly used, while Bakelite, leather, porcelain, and other less durable materials are also known.
Local stores, saloons and mercantiles would issue their own tokens as well, usable only in their own shops. Railways and public transport agencies have used fare tokens for years to sell rides in advance at a discount.
The key point of difference between a token and a coin is that a coin is issued by a governmental local or national authority and is freely exchangeable for goods or other coins, whereas a token has a much more limited use and is often (but not always) issued by a private company, group, association or individual.
In the case of “currency tokens” issued by a company but also recognized by the State there is a convergence between tokens and currency. The best known example, the trade tokens of Strachan and Company, were issued in South Africa in 1874 and are today recognized as that country’s first widely circulating local currency.