I saw this display at a public library. I thought it was such a lovely idea that I took a photo with my cellphone so I could share it with all of you. This library has taken books in like new condition, tied them together with a festive bow, and placed them for sale.
It would be a simple idea to copy. Most libraries have donated books for sale. You could bundle together books by one author or even group books in the same genre, like romance or mystery. Stop by a craft store for a ribbon bow and you are good to go with a thoughtful gift that will also benefit your local library.