I always recommend half.com as a source for used books. I've gotten some great deals from them. They're generally comparable to Amazon's used sellers. I've only been burned once by a vendor who confirmed the order but then never shipped and never replied to email. I did get my money back, but it certainly screwed me up at the start of the semester.

I would also recommend doing a mental health self-eval the day before the test. If something bad has happened, don't be afraid to call the testing center and reschedule the exam. I was scheduled for my CCNA exam and two days before it a friend of mine died unexpectedly. As he was younger than me and pretty close, this really rattled me. I failed the test by 3 points IIRC, it could have been as little as one question. I sailed through it on the retest, but don't be afraid to push it back if you have something nasty happen just before the test.

I think that overall a degree in an IT field is more useful than a cert, but having the cert plus the degree is definitely good. It's all a matter of getting through HR's filters. I had to do a technical eval on a PC because I didn't have the degree, and I got the job, so I guess I did OK. THE FOOLS! I'LL SHOW THEM ALL! BWAHAHAHAHAHA!