Tracy, who seems to come up with brilliant hacks on a weekly basis, found this one at Tipnut, from Betty Russell:
For years used cereal bags for icing! The wax paper is nice and heavy and easy to turn into a pastry bag. Cut a small angle on one corner or open flat and form a cone with an opening the size you want. Scoop icing into it and twist down as needed. No cleanup mess just toss when done! Strong and flexible…will not fall apart when using.
As Tracy says, "Wow! What a HACK!!!!! Makes me want to bake a cake just to try it out!!"
Full post at Tipnut: 20 Things You Can Use Twice Before Tossing