If you find a scholarly article on the free web, the Unpaywall extension in your browser will indicate whether an open access version of the article can be downloaded.
The JSTOR database open access module contains academic content that is open to everyone, anywhere. Search free articles and open access book chapters.
If you're looking for examples of how other instructors have approached teaching similar material, consider visiting the Open Syllabus Project. You can search by title (e.g., They Say I Say), authors, and discipline.