Yapta (www.yapta.com) provides help to get a refund on your airline ticket after you've purchased if the flight price drops. Of course, you not only have to consider the drop in price, but also whether adding in the change fee will still make re-booking worthwhile. Yapta does not secure the refund for you, but it advertises that it will send you an alert if the price of your ticket has dropped, and it will give you all the information to speedily get your refund, so you can re-book at the lower price. Yapta is a reputable company, mentioned in major publications, and it can monitor any airline that Kayak tracks, since that is the engine it uses. I've not used Yapta, but if you have, and it's saved you money, please let me know. I'll share your story on the blog, if you'd like.