Carton of cigarettes (Fallout 3)

A carton of cigarettes is a junk item in Fallout 3 and Fallout New Vegas that can be sold or used as ammo for the Rock-It Launcher. Cartons of cigarettes are relatively light and are worth 50 caps. They are the most common of the three groups of cigarettes that are found in the Wasteland and can frequently be found in the general stores of the wastes, garbage cans, and office cubicles of destroyed buildings, often resting on desks, or on the floor.

Fallout New Vegas
In Fallout: New Vegas cartons of cigarettes are quite numerous. In fact they're found nearly everywhere. A character with a lot of space can capitalize on their value and easily make a few hundred caps from finding and selling them out in the Wasteland.