It's wrong for a roommate to not pay rent.
Justin and Harry are roommates who share the rent, and Harry almost has enough money for a car.
Harry wants to buy a car.
Harry pays his part of the rent and saves up one more month for the car.
Harry uses his share of the rent money to buy a car.
Justin and Harry continue living together, and Harry can drive to work.
Justin is angry and kicks Harry out of the apartment.