Openstax has free textbooks for various college courses. Their Elementary Algebra text covers a standard Algebra 1 course, and the Intermediate Algebra course Algebra 2. There's also Prealgebra, Algebra and Trig, College Algebra, Pre-Calc and 3 semesters worth of Calculus to round it off. Only drawback - the are no answer keys; you need a school email address for Instructor access to those. There's also a High School Section with AP courses: History, Physics, Micro/Macro Econ, and Stats.

Has anybody looked at the new edition math books from BJU? From Grade 6 to PreAlgebra the books have a much cleaner look to them. There seems to be more white space on the page, and there isn't so much 'clutter'. I really like them.