Technically you could then look for flights using other booking websites or your favorite. Kayak che

Unfortunately, booking a bargain flight has become an evil puzzle which I am constantly trying to figure out. I did come across one cool new tool that helps when you are fairly flexible with your plans as a real vagabond should be!
So many times when vagabonding or planning lastminute travel deals a trip, the price of a flight was more important to me than the actual destination. For instance, if I just wanted to wander Europe, I would be willing to change my port of entry to save a few hundred dollars. It makes little difference to me if I fly into Brussels, Frankfurt, or even London because of cheap budget airline lastminute travel deals options such as RyanAir that can shuttle me around for cheap or even free sometimes!
Why not save a few bucks flying into a cheaper city and then catching a budget hop to my planned destination? Many people trying budget travel basically just want to get to the continent with the cheapest airfare possible.
Kayak will check for recently booked flights to that continent from your airport code and give you the rundown. You can then click to see if the current fare is still there or has gotten even cheaper (hopefully).
A quick glance at the results screen tells me that it is cheapest for me to fly into Frankfurt, Germany right now! I never would have guessed that and probably would have been looking at flights to London which one would think is the travel hub of Europe.
Technically you could then look for flights using other booking websites or your favorite. Kayak checks around 450 sites and typically brings up pretty good fairs for me.  I ve got some hints and tips for booking cheap flights on my backpacking site.