The black market is the trade of goods illegally. Black markets operate outside the normal economy. The black market is different from the so-called Grey market, where goods are traded legally, but outside the common channels. Goods and services traded on the black market include drug and arms trafficking as well as prostitution. In some casess, the goods or services are cheaper than on the normal market, because taxes or production costs do not need to be paid - very often the goods traded were stolen. In other cases, the price on the black market is higher, because the goods are difficult to get, producing or handling them may be dangerous. Some drugs are illegal to produce, their price on the black market is often higher than the production costs. Even though such a market is not controlled by the state, the economic principles are still that of a market: supply and demand influence the price.