I think a good study guide must consist of both the material breakdown and sample questions. The study guide at NREMT Academy (http://NREMTAcademy.com) have a lot of material breakdowns and online mini tests that will help any EMT-B test takers to feel confident when taking the National Registry. Paying a small price for a study guide is definitely worth it. You will understand and be confident to pass the test. The EMT-Basic curriculum from the AAOS book consist of a lot of redundancy. By using a good study guide, you will be able to focus more on what are essential on both passing the National Registry Exam, as well as being a good EMT. You already spend a lot of money and time to become an EMT, a small price for a study guide shouldn't be a big deal to get. At the end of the day it is cheaper to get the NREMT Academy study guide and pass the exam, rather than having to retake the exam cause you failed.