If you are worried about the cost of a few books that will make you smarter and better at your profession you probably won't ever be a very good electrician.
Where are you taking the test? Did the testing agency give you any ideas as to study guides? That's usually the best source to get material closely related to the difficulty of the test you are about to take.
If that doesn't help look for books by Tom Henry. He's located in Florida. Also the IAEI books are not bad either.
Don't skimp on being an excellent electrician by limiting your knowledge because a book is expensive. No matter how expensive a book that teaches you something is, it's the best money you'll ever spend.
There is absolutely nothing wrong with trying to be frugal with your money. Study guides with practice question and answers are nothing more than a vehicle to help you pass an exam. Study guides are fantastic tools, but all of the knowledge that is important is in the NEC. If a study guide is such a great tool and is supposed to make you smarter and better at your profession, I challenge you to give me one instance after you took the examination that you referenced the study guide instead of the NEC to help you solve a code issue?
If you do pass your exam with borrowed reference material, you will wish you had access to it again at some (many times) time in the future. Do buy your research material, but shop around. As Steve said, Tom Henry has excellent prep material, you can also look at Mike Holt and James Stallcup.