Reddit mentions of Trigonometry Refresher (Dover Books on Mathematics)

Be wary when looking for books on algebra. They can often be confused as abstract algebra/modern algebra and just be titled algebra. At your level, you do not want abstract algebra (group, field, ring theory, etc)

I recommend, by nothing more than looking at their table of contents:
Algebra:
http://www.amazon.com/Fundamental-Concepts-Algebra-Dover-Mathematics/dp/0486614700/ref=sr_1_4?ie=UTF8&qid=1418411228&sr=8-4&keywords=Intermediate+algebra+dover

Trig:
http://www.amazon.com/Trigonometry-Refresher-Dover-Books-Mathematics/dp/0486442276/ref=sr_1_2?ie=UTF8&qid=1418411383&sr=8-2&keywords=Trigonometry+dover

Geometry: This book may go a bit too advanced, but it is cheap and seems decent
http://www.amazon.com/Geometry-Comprehensive-Course-Dover-Mathematics/dp/0486658120/ref=sr_1_1?ie=UTF8&qid=1418404358&sr=8-1&keywords=geometry+dover

Calculus: This is by no means comprehensive(it seems to lack p tests for divergence among some other topics in cal 3), but it is enough to get you ready for advanced topics in it.
http://www.amazon.com/Essential-Calculus-Applications-Dover-Mathematics/dp/0486660974/ref=sr_1_1?ie=UTF8&qid=1418404423&sr=8-1&keywords=Calculus+dover

If you are interested in linear algebra, check out Shilov's linear algebra textbook. Don't bother with abstract, it really isn't that useful in engineering(computer science... yes)