Fancy folder, with button and cord closure will hold sheet music or a book of music ---
or school papers plus a composition book ---
or brochures and reports and other business papers.

The paper is protected on the outside with plastic and on the inside with cotton duck canvas.  The plastic makes it water resistant.  The cotton duck makes it stitchable and sturdy and long-lasting.
 

Prices range from $20 to $30.