Online Algebra 1 2 and Pre-Algebra Textbooks

cK-12 has several free online digital algebra and pre-algebra textbooks for students and teachers in grades 6-12.  There are editions for students and teachers, and textbooks that include the use of graphing calculators for Algebra 1 and 2.  You can read the textbooks online or download them.

There are also accompanying study guides for algebra topics.