It's no big deal. If you want a test run at it just take it. Taking it twice won't hurt you, but yeah more than 3 times maybe.
I actually intentionally skipped a test too back in Oct because I didn't feel ready and just forfeited the fees. I had already taken it once, but I just got really nervous the day before so I didn't go. If you're Canadian (I am too), yeah the fees are hard to swallow especially with our crappy dollar but whatever, in the long run it's just a tiny blip of what you'll have to pay in tuition.
Are you applying this cycle/ have you already applied?