OpenStax textbooks are available as FREE downloads in PDF, Web, and EPUB formats.  They also offer professionally printed copies for a low cost, as well as interactive e-books, which can be purchased for $4.99 through iTunes.

Available Now:

College Physics

Introduction to Sociology

Biology

Concepts of Biology

Anatomy and Physiology

Introductory Statistics

Coming Soon:

Pre-Calculus (Summer 2014)

Chemistry (Early 2015)

U.S. History (Early 2015)

Principles of Economics (Spring 2014)

Principles of Macro-Economics (Spring 2014)

Principles of Micro-Economics (Spring 2014)

Psychology (December 2014)

• Click here to go directly to the OpenStax College site

• Started by Rice University, powered by ConneXions and funded through various foundations.

• All OpenStax College textbooks are hosted on Connexions and can be customized by you to fit your classroom needs.
• Where as ConneXions has various modules that you assemble, OpenStax starts with an entire textbook that you can modify
• Supporting materials available such as solutions manuals and teaching guides.  Source