Open Educational Resources (OER) "are teaching, learning, and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others. Open educational resources include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge." (Definition from the William and Flora Hewlett Foundation)
“Open Educational Resources as Learning Materials: Prospects and Strategies for University Libraries,” Marilyn S. Billings, Sarah C. Hutton, Jay Schafer, Charles M. Schweik, and Matt Sheridan, Research Library Issues no. 280 (Sept. 2012).
Make Textbooks Affordable (Student Public Interest Research Groups—PIRGs)