From time to time, many airlines offer specials on airline flights to popular destinations. You just have to be able to find them in time, and make your reservation right away. Often there are limitations on when you can fly but sometimes you are given a six month window.
A website called The Flight Deal, has found an interesting special, going from Seattle, Washington to Tokyo, Japan for only $664. Not only that, this covers a round trip, flying to Tokyo and back. In addition, it is on American Airlines (AAL). Plus, that $664 fare includes taxes.
If you keep your eyes open, you can find deals like this.