Journal Publishing Agreement (JPA) addresses what authors can do with different versions of their manuscript - e.g. use in theses and collections, teaching and training, conference presentations, sharing with colleagues, and posting on websites and repositories.
ACS Articles on Request provides a unique URL within the ACS Web site, that authors may email to colleagues or post on external Web sites
Because of Western' subscription to the ACS All Publications Package, you can take the discounted price to publish open access journal articles with ACS. Please check this document for the detailed pricing information.