These are hands-down the best bags for music! I love these bags because they are big enough for lots of books and a binder, but it's not very bulky. Each bag comes with a pocket on the outside and a small pocket on the inside. I find that my kids can keep all of their music supplies in their bag in the various pockets. It includes a matching coin purse.
12" x 12" x 4" Microfiber or canvas fabric with a flat bottom.