FlexMath is a free online basic course in algebra.  It is designed for use in conjunction with classroom instruction, and it guides you through 9 units and 84 lessons up to quadratic equations.  It’s a flexible alternative for students with heavy sports schedules, who are ill for extended periods of time, and for homeschoolers with parent instructors.  Teachers and students can track their progress, and teachers can create a calendar with assignments and due dates.