basically the same as crackwhore. There are some subtle differences though. Someone who gives sex for crack money is the definition of crack whore. A crack slut claims that they need the money to buy crack and give sex, but really have enough money without giving sex for crack, and give sex anyways. So basically they are sluts, who are addicted to crack, but dont need the money from the sex.
Person 1: A crackslut is having sex with my dad in my bedroom.
Person 2: Shutup bitch
Dad: Heres some crack money