OpenStax

OpenStax is a nonprofit that partners with colleges to create free, open-source textbooks for the most commonly taught college courses. These books are peer-reviewed by subject experts and regularly updated, offering a real alternative to commercial textbooks that often carry steep price tags.

It's designed for college students looking to avoid textbook costs and for instructors wanting to adopt lower-cost materials. While OpenStax doesn't teach courses directly, its textbooks support thousands of college classrooms and serve students who otherwise might skip required readings due to cost.