If you're confused about the best place to buy airline tickets here's a tip: AVOID Travelocity, Orbitz and Hotwire. Use a fare comparison aggregator first. They aren't travel agencies, they are resources that check several (and in some cases, hundreds of) websites for the best deal, something you'd be hard pressed to do as a mere mortal.
Those sites include ...
All are good for checking fares and comparing with Mobissimo being exceptional at International fares. Go ahead and check them now, links open in a new window.
NEVER go to an airline's site directly unless it's Southwest (unavailable through aggregator fare services). You could take the step of seeing who has the best deal and then booking directly on a carrier's website though.