Check in with teachers and find out if they are using the same textbooks the next academic year. Contact parents with children in the current classes and arrange to buy the used textbooks.
Organize a book exchange at school where parents can trade used textbooks. Work with the school administration to set up the main event on registration day when the bookstore is open selling new textbooks. Consider setting up an uniform exchange, too.
Visit the American Book Exchange website for used and reduced-price copies of needed texts. Enter the title, author, publisher and/or the ISBN number to locate a text. Contact the seller to make sure the book is available and arrange to purchase it.
Check out the Alibris website, a network of individuals and small shops selling new and used books. Search for a specific title by entering the relevant information and then contact the seller to complete the transaction.