I usually just make a form from cardboard and cover it in tape, but I wanted something a little sqishy-er and bigger this time around. I took an old freebie bag from a library conference, similar in shape in texture to a reusable grocery bag, and cut it down to the size I wanted.
I covered the whole deal with tape and added rivets and ribbon for straps. It's big enough to throw in a book and a snack, so I'm ready for summer!
Once again, duct tape proves that it is good for it!