A black market is a virtual or physical platform where people exchange goods and/or services that are illegal or are sold in an illegal manner. They typically skew economic data in order to keep their transactions undetected. Black markets exist either because of a demand for these illegal goods/services or for tax evasion. Some secondary markets can be considered as black markets.
Typical things that you might find on a black market are: illegal drugs, prostitution, knock off designer brands, ticket scalping services, human organs, endangered species, human trafficking, and smaller things.
Slide: 3
Black markets really began during WWII as a way to get around the rationing standards that were put on the citizens for the sake of the war. The term black market first appeared in the 1930's.
Producers, suppliers, and consumers of all economic/social statuses took part. Black market trade included steel, tires, coffee, sugar, gas, butter, processed foods, meats, and ration coupons (both real counterfeit).