Though fewer and fewer grocery stores give you the choice anymore, the next time you are in a store that asks "paper or plastic?", answer paper.
Thanks to a post by SayUncle about a guy using a selection of Priority Mail boxes to make cardboard silhouette targets, I found this:
You can make two paper silhouette targets from one large paper grocery bag. That is what I call ingenuity! Full instructions are at the link above.