This is the same study guide for $40, right?
$175 for the exam voucher + $40 for the study guide = $215. This means if you pay $300 (not including $17 for shipping) to CWNP, you are effectively paying $85 for their practice test. Is it worth it?
If you are new to wireless (i.e.< a couple years active) and you have not taken the exam before, it is VERY doubtful you would ever pass the real exam without taking the practice exam (several times).
The few dollars you save on the book by itself, isn't worth it. You'll be very pissed at yourself afterwards too.
This not a relatively simple Comptia test.
I know several people who passed the old CWTS just by reading its (CWTS) book, but the CWNA test is an order of magnitude more difficult.