Open Educational Resources are a sub-category of openly available content. All Open Educational Resources are Open Access, but not all Open Access content is OER.
Pre-print: The accepted version of an manuscript before it has gone through peer-review or copy-editing.
Post-print: The final accepted version of a manuscript, after peer review, but before any copy-editing or formatting by a publisher.
Open Educational Resources are educational resources published or shared under a Creative Commons license (excluding those with no derivative clauses) or released into the public domain, allowing for adoption, modification, and redistribution of the content in service of learning.
Faculty: Content can be edited to fit course needs.
Students: OER is freely available. Textbooks would be no cost.