The group has been facing financial crisis after US led coalition forces carried air strikes that led to territorial defats.
"A post on Facebook showing a picture of a girl was attributed to an Islamic State fighter who calls himself Abu Assad Almani. The post read: "To all the bros thinking about buying a slave, this one is $8,000," reported the Washington Post.
A picture of another sex slave was also posted by the same man on the Facebook for sale.
Another sabiyah [slave], also about $8,000," the posting reads. "Yay, or nay?"
According to report, the photos were later removed by Facebook.
An Amnesty International had reported that ISIS has captured thousands of women and girls, as "brides for jihadis" from Iraq and Syria reportedly in in Bardoush prison in central Mosul.
Not only young girls, some children too were being sold to the militants as 'sex slaves' or given as 'gifts'.