I agree with Pam EXCEPT that I use Travelocity (which always seems to have the lowest "normal" rates) before I call the airline. Knowing what I can get it for on Travelocity helps get me the lowest price from the airline and sometimes the airline does even better. Also keep in mind that most of the web sites quote only the base rate (not including taxes, gate fees, terrorism fees, etc.). When you talk to the airlines they quote the TOTAL fee.
Actually the best way to travel is FREE. My trip to the convention was on a free bump certificate and we got bumped once on the way there so we now have more free travel coming. We got the original certificate when we were in Florida and three of us got bumped off of the plane and had to stay overnight. Got $750 EACH in free travel on Delta. My daughter used hers to visit a friend in Marseille France a few months ago and we still had enough left to take all of us to Las Vegas. More good news is that most airlines will let you accumulate frequent flyer milage even when using the free tickets! Sometimes you can even get bumped more than once at the same airport. I once was bumped twice at Detroit and arrived home a whole 2 hours late. It's lots of fun if you can spare the time. Try it.