Linear Algebra by Jim Hefferon – free textbook
It's nice to have a free book as a supplement.  Linear Algebra Done Right by Sheldon Axler is a much better choice and when making an investment in learning, particularly a difficult subject like linear algebra, saving money with a free text is probably the most expensive thing you can do.  You might save $40 but end up not really learning and wasting hours you don't have.  Above all, find a good teacher.