I've never taken a FL exam, but I'm going to give you my advice anyway...
This is an open book test, right? So if the State is going to let you to use these books during the exam, then why would you consider NOT buying them? It seems counter-intuitive to me to willingly go into a test without every reference you can legally use.
If you save money by not buying the books, then flunk the test and have to pay to take it again, how much $$ did you really save?
Also, FWIW: A quick Google showed at least 2 sites renting the complete exam set for the FL tests, for ~$300. Maybe do that, instead of showing up to test day without all the references.