Where are you wanting to fly, though, within Europe? If you are having to pay for the intra-Europe flights and are attracted by the idea of our "burgeoning" low-fare sector, these sites may point you in the direction of the appropriate airline websites for the routes in which you're interested. Many of these airlines won't sell through the big online agents and you have to go to them directly.
http://www.skyscanner.net/wings.asp
http://www.openjet.com/public/index.jsp
("Burgeoning" - got to love that press-speak!)