Here is a link to the paper from sam's. for the little difference in price, I would buy the sure thing.
I'm sure that quality butcher paper is available lots of other places too. If you need just a little bit, ask your butcher... i'm sure that he would give you a piece or two (if you are buying your meat there)
18.5 WSM, Green Weber Genesis320, Cast iron firepit(w/grill), and a Copper Weber 22" OTS