Facebook Marketplace Low Baller. Someone who offers way less on a marketplace listing that it either goes two ways: They accept it and make a deal, or they tell you to go kick rocks.
FBMPLB - "Hi, is this available? Would you do $1000?"
SELLER - "Fuck no dude the lowest i will go is $4000"
FBMPLB- "Bro you are smoking that car is not worth $5000"