It depends on how bad you want to pass and how high a score you want. I pick up used books on amazon and save a lot that way. I have no problem dropping money on diffrent books because I still am saving a ton of money by testing out. For 60 or 70 dollars worth of books you can test out of a 700 or 900 dollar course. Still a deal. The extra money also pays off in not having to test again because you nailed it the first time. Read the book reviews on amazon to see the best books to use. The 20 a month on intsantcert has probaly saved you thousands already.