Best rates for airfare?

There is no one cheapest website for international plane tickets. If there was, everyone would go there. I suggest you start off with http://www.kayak.com/ and http://www.skyscanner.net./ Also check out the airline's own website. Know that ticket prices will depend on if you are flying during peak or off-peak season. Therefore I suggest you find out when peak travel season is to the destination(s) you are going to and avoid going there during peak travel season.

Always search in the morning for flights because that is when airlines update prices. Usually, I check at 3:00 am. I know, thats really early, but it helps. Also, before, delete ll of your history, and cookies. I don't know how it helps, but it always reduces the prices. But it only works in the morning like before 5:00 am. I got a ticket to London from JFK using British Airways for $782 in prime time. I always use Cheapoair for my travel needs because they usually have the best prices. After cheapoair, I would suggest Expedia. Expedia is more better for Hotel booking though. If you would like to test your chances of luck, go to priceline and name your price, to see if any airline is willing to accept your offer.

Chuck look at Orbitz, Expedia, Kayak, Flight Center. Also have a look at the Airlines web sites directly, they have some good deals to destinations.

Orbitz.com

also, deleting cookies. and looking up prices early in the morning (around 4am)

Make sure that you delete the cookies in your Internet. It'll reduce the price- trust me!