I do not understand why nobody mentioned Schaum's Outline of Theory and Problems. These books offer a lot of practice in different branches of math. From algebra to calculus to differential equations,logic, topology,...

It has always been a great idea to practice my math skills with the problems there.

Another thing, I learned calculus I to III before getting in to univ from the book:

 [CALCULUS: An introduction to Applied Mathematics by  H.P. Greenspan (Author), D.J. Benney] [1] You will definitely find it in most university.

Also I learned Group theory (again before getting in to univ) from:

 [Algebra (2nd Edition) 
Michael Artin][2]

My final remark: You will get high-quality math ebooks for free from the internet, a great repository of knowledge for everyone.

  [1]: http://www.amazon.com/CALCULUS-introduction-Mathematics-Harvey-Greenspan/dp/0962699810
  [2]: http://www.amazon.com/Algebra-2nd-Michael-Artin/dp/0132413779/ref=dp_ob_image_bk