Open Education can include free online textbooks and lessons, and other open access learning tools. Many studies have shown benefits in using Open Education Resources : http://openedgroup.org/review
Open Textbook Library: Access to textbooks in all subject areas, making textbooks affordable (free) for students.
MIT Open Courseware : Publishes course materials online to make them widely available to everyone.
MIT OnlineTextbooks: Available to serve as an alternative to conventional textbooks.