Sometimes it's a good idea just to call the airline (CALL, not go on their website). A week or so before the flight, they are so willing to have a full flight (the only way they can really break even) that they will sell it at the lowest possible price in order to do that.
I have a lot of experience with flying and getting reasonable tickets--between living about 2,000 miles from my school, being in a long-distance relationship, and studying abroad, I've had my share of good and bad cheap fare hunts.
