Free math

Totally Free Math is a
free math textbook written by math teachers who dislike the typical practice of textbook publishers, which is to gouge every last drop of blood from math and science students. For those of you who studied other fields, I'd say my average textbook cost was about $80-$125 per book; and publishers usually come out with a new edition of rehashed material every couple of years to keep students from buying used textbooks from upperclassmen. A friend of mine studying physics tells me that he pays as much for three books as his sister does for eight. It's hard out there for a geek.