I am always looking for great ways to ship using recycled products. I have a good way to ship books safely while using recycled materials. I have had good success with this shipping method, as I have never had a package damaged in the mail.
First, I wrap the book in a clean plastic bag. I feel this is important, especially as some areas (like the South, where I live) are much more humid. This helps protect your book.
Then I tape the wrapped book to a piece of corrugated cardboard that is just a little bigger than the book size. I get free, clean corrugated boxes at the liquor store in my neighborhood and cut them up, so I keep a stock of cardboard in the house.
If the book is more delicate, like a Wonder Book or Little Golden Book, I tape a layer of Bubble wrap over the unprotected wrapped book.
I then put the wrapped book in a manila envelope, tape with clear wide packing tape, and I am ready to print postage.
I love the printed postage from Paypal. I print labels on regular computer paper and affix it to the package with clear wide tape.
I hope these book packaging suggestions are helpful! If you have other green-wise packing suggestions, I would love to hear them as well.