Some free blacks did own slaves. Others bought their own relatives to get them out of slavery.
There were also a number of skilled free blacks, such as tailors, shoemakers, and carpenters, who bought slaves and made them apprentices.
In 1850, 19 percent of the black tailors in Charleston, South Carolina, owned slaves. According to the 1830 census, 753 blacks in New Orleans, Louisiana, owned slaves. Slaves were also used by free blacks as maids or day workers.
A small number of blacks owned slaves for the same reason as whites did: to perform the labor in their money making operations, such as farms.