As far as I could find out in some states of the South women could be slave-owners with equal rights as any male slave-owner and daughters overtook lots of slaves including the plantation after their parents when they were regarded to be more clever as their brothers. So it seems to me that in some states women were emancipated and could have the same rights as free men and therefore also buy and sell slaves.

In vestern nations it usually was not that women could not inherit, but that they were not considered competent to administer the property they owned. A male guardian had to be assigned to do that. If she was married that would be her husband or it could be a family member or sometimes a law firm. As owner the woman could then make suggestions, and the guardian could chose to reject or implement them as the ultimate authority on matters financial. Some routinely accepted her suggestions, others ignored them. And as you may imagine a lot of inherited assets were mysteriously transferred to the coffers of less than trustworthy guardians. regards JakobA

There is a story here in Lexington where a black woman bought a white man in the early 1800's. "Aunt Charlotte was a slave brought to Lexington, KY, in the late 1700s. She was freed and inherited property after her owners died. She supported herself by selling fruit and baked goods at the open market. She and William "King" Solomon had known each other in Virginia, and Aunt Charlotte's story is tied to his in the literature. Solomon was a white vagrant who supported his drinking with wages earned as a digger of cisterns, graves, and cellars. In the spring of 1833, as punishment for his vagrancy, local officials put Solomon up for sale as a slave for one year; at the end of that year he was to return to court. Aunt Charlotte purchased Solomon for $13...Aunt Charlotte set Solomon free, and he promptly managed to get liquor, later making his way back to Aunt Charlotte's home, where he passed out on a Thursday. He woke on a Saturday to find that many had died or were dying of cholera while others were evacuating the city. Aunt Charlotte was preparing to leave, but when Solomon refused to go, she would not leave him. People were dying quicker than they were being buried--the gravediggers had deserted the city. Solomon took up his shovel and began burying the dead. His dedication probably prevented further spread of the disease. Both Solomon and Aunt Charlotte survived the epidemic. When Solomon returned to court, the judge shook his hand and others thanked him for his heroic deeds." ~http://www.uky.edu/Libraries/NKAA/subject.php?sub_id=112 His large grave, bought for him by other citizens to honor him when he died several years later, is easily seen in the Lexington Cemetery.