There are more options and tools than ever to help you time when to buy your airline tickets at the lowest price (as we have written about before). Now there’s a service that allows travelers to track the price of their booked flights and receive alerts when the price drops, so they can re-book their seat and save.

Yapa, a free service that’s been tracking airfare since 2007, let’s users track airfares on desired flights and sends alerts for the best time to purchase. “Get the best fare, even after you buy,” is the headline that greets you on their website.

If you have already purchased your seat you can also track the flight and receive price drop alerts. Their system takes into account rebooking fee’s prior to issuing an alert preventing any rebooking disappointments. Forward your itinerary confirmation email to to begin the price tracking service.

According their website, Alaska Airlines offers refunds for any price drop; Jet Blue and Virgin offer refunds for price drops of $75 or more; Hawaiian Airlines will refund any price drop greater than $100; and United, Delta and American will refund any price drop more than $200. They claim to have saved users over $3.5 million, and an average of $334 per user.