Even when I got to just over one PAD, sometimes, I still only bought two at a time, unless the gas station near my house happened to have a carton of the special priced ones, still (they sold out really fast). Mine were usually 2/$7.01 on sale, which was cheaper than buying a regular carton (saved about $7 by not buying the carton, maybe more). We bought cartons a few times in the years before the "special prices," though.