I've known some folks who have gotten great fares by flying to a nearby US city(or driving I suppose) and grabbing some of the VERY cheap wholesale fares available on some US carriers. I've had success with a great a very helpful young lady named Amanda at ComeMonday.com. Her email address is [email protected]
I guess it all depends on what part of Canada you're in. Good luck. I'm booking right now for November. Can't wait to get back to paradise.