Single cigarettes bought in
Detroit (or any urban area) off of gas station workers. Usually .50 cents each, the logic is that if a worker takes a pack, smokes half and then sells half he makes his $5.00 back that the pack would've cost him.
Also a safer way for gas stations to sell to minors, since the
kid can just throw the cigarette on the ground when the
po-po rolls by, and not have a pack on him.