Free Algebra Ebooks

Elementary Algebra and Trigonometry Ebooks

1. Advanced Algebra II: Conceptual Explanations by Kenny Felder
2. Advanced Algebra II: Activities and Homework by Kenny Felder
3. Algebra I by  CK-12 Foundation
4. Algebra in Simple English wikibook
5. Basic Algebra and Trigonometry by Thomas Ward
6. CK-12 Trigonometry by Mara Landers and Brenda Meery
7. College Algebra by Carl Stitz and Jeff Zeager
8. Elementary Algebra by Denny Burzynski and Wade Ellis
9. Elementary Trigonometry by W. E. Paterson
10. Intermediate Algebra by Department of Mathematics, College of the Redwoods
11. Intermediate Algebra by John Blakely
12. Teach Yourself Trigonometry
13. Trigonometric Delights by  Eli Maor
14. Trigonometry by Michael Corral

Abstract and Linear Algebra

1. A First Course in Linear Algebra, by Rob Beezer.
2. A Second Semester of Linear Algebra by S. E. Payne
3. Abstract Algebra by John A. Beachy, William D. Blair
4. Abstract Algebra On Line by John A. Beachy, William D. Blair |
5. Abstract Algebra: Theory and Applications by Thomas Judson
6. Abstract Algebra:The Basic Graduate Year by Professor Robert Ash
7. Algebra: Abstract and Concrete by Frederick M. Goodman
8. Elementary Linear Algebra
9. Elementary Linear Algebra, by Keith Matthews.
10. Elements of Abstract and Linear Algebra by  E.H. Connell
11. Linear Algebra and Jim Hefferon
12. Linear Algebra by Macquarie University
13. Linear Algebra and Matrices by Martin Fluch
14. Linear Algebra Done Wrong by Sergei Treil
15. Linear Algebra by Professor Jim Hefferon
16. Linear Algebra for Informatics and José Figueroa-O’Farrill
17. Linear Algebra: An Introduction to Linear Algebra for Pre-Calculus Students by Tamara A. Carter, Richard A. Tapia, Anne Papakonstantinou

Other Algebra Books

1. A Course in Universal Algebra, by Stanley Burris
2. Lie Algebras by Professor Sternberg

You may also want to check my Free Calculus Ebooks post.