Nobody likes to purchase a new book that has evidence of use—shrink wrapping books keeps them in good condition prior to sale. There are various shrink wrap plastics, but the best is Polyolefin. It shrinks without a lot of heat and does not contain plastisizers that smell, and possibly damage books. Use 7 1/4" x 10" shrink bags for 8 1/2" x 5 1/2" books that have up to a 1" spine. The DVD case bags from BagsUnlimited.com work well. Shrink wrapping adds about $0.06 in materials cost to each book.
A sealer and heat gun are required for shrink wrapping. Uline has impulse sealers in several lengths, ranging from $60-$210, and an industrial heat gun for about $60.
Insert promotional materials about available books, etc., at the back of each book before shrink wrapping.