The academic textbook market is an interesting space. Traditional commercial publishers provide a valuable service to authors and consumers alike, but the cost of traditional textbooks can be a little beyond the reach of some students. In many cases, the foundational knowledge of a field does not change significantly over the course of 5-10 years (if not longer...), so the benefit of a $100-300 shiny new textbook is minimal. For this, and a variety of other reasons, I have embraced the Open Educational Resource (OER) philosophy and strive to choose OER textbooks and other resources for my classes. A couple important notes:

1. I will not choose an OER textbook just because it is OER. I review these textbooks and I will only adopt them if I feel that they are of sufficient quality to provide a useful resoruce for my students.
2. Just because an OER is "freely available" for students to use does not mean that it is a magically free piece of knowledge that was mysteriously plucked from the ether. Compiling a textbook takes work. Writing a textbook takes work. The creative people who perform this work should be recognized and compensated for their efforts. This is why I feel it is important to recognize the organizations and generous donors who make OERs possible.

General Chemistry - "Chemistry 2e" (from OpenStax)
General, Organic, & Biochemistry - "Introduction to Chemistry" (from Saylor Academy)