Yapta
Try this site now. It tracks the cost of flights that you are thinking about purchasing and/or have already purchased so you can get the best deal. You purchase your tickets direct through the airlines though not this site. In July I bought two plane tickets on Northwest Airlines flying from Albany to Bozeman, Montana. This is all part of a secret trip I am planning for Joe's 30's birthday. Anyway each ticket was $520.50 after taxes/fees yadda. I tracked the flight on Yapta.com and got an alert yesterday that the price of the flight dropped to $345.99 so I called Northwest last night and they gave me two flight credits for $124.50 (the difference between what I paid less a $50 fee per ticket). The credits are good for a year. Some airlines will actually refund your money, Northwest is supposed to be one of those airlines but I was pressed for time last night and didn't feel like arguing on the phone for an hour. If you do get a refund it for the difference in price less a $100 fee (through Northwest anyway) which is only worth it if you don't travel often. Of course I am irritated that I could've saved $400 if I would have just waited another 2 weeks to book the flight BUT I am so excited to have a credit toward a future flight, especially since we are going on vacation in December and again in April and I haven't booked the flights for either trip yet. Hopefully now between our frequent flier miles and these credits we'll fly for free! YAY. Try yapta, you'll love it!