Slave Markets 

They sold slaves to labour plantations that grew cotton, rice, tobacco and sugar cane, because these crops needed a lot of labour, slave owners started buying slaves, directly from West Indies and later in the 1700s the bought directly from Africa.
Philadelphia, Richmond, Charleston and New Orleans were among the  major cities in America where slave markets started growing rapidly. Owners of slaves would hire them out if they did not have work for their slaves for half the original price. 

In 1711, the New York City Council passed a law requiring all African and indigenous slaves and native Americans who were for hire to be rented out at a special market known as the Meal Market, which was located at Wall Street slip close to the East river. 

The region grew to becoming the biggest slave hiring and buying centre. Slaves had already travelled great distance from deep  Africa to the coast. They were often sold and bought mutliple times during this journey before finally arriving at the costal slave market (SAHO, 2015).