Do not tape the printed bag
If your supermarket no longer offers cosmetic packaging, buy a roll of the brown paper designed for gift wraping and use that instead. Cut a piece long enough to cover the front, back and spine of the book with at least three inches of overlap at either end. Do not tape the printed bag to the actual cover of the book; the paper cover will move a little when the book opens, and you could damage the book cover. If your child likes and the teacher allows, decorate the cover with custom bag or stickers. http://www.niceindustry.co.uk/about.asp