As far I know the state of Kentucky has the cheapest carton of cigarettes and cheapest packs of cigarettes.
A pack of cigarettes in Kentucky costs around $5.40 and there's 10 packs of cigarettes in a carton of cigarettes so a carton of cigarettes in Kentucky would cost you $54.00 before tax.
You might find some cheaper cigarettes in other states but from what I've read online before Kentucky has the cheapest carton and packs of cigarettes.
Still cigarettes are pretty expensive in all states anyway and really bad for health and I'm glad I quit smoking cigarettes years ago as I save a lot of money.