Do students need to buy the textbook if my institution already has access to the textbook?
No, but students may wish to purchase their own copy for access after they leave your institution. This will also enable the student to preserve bookmarks, annotations, and other customisations they have made during their access via your institution.
Print and digital purchase options are available on the textbook page, but students who attend institutions with access already will not see prices until they select any purchase options.