How to buy low cost flights?

Here is a list of site to find cheap flights:


http://www.bravofly.com
http://www.kayak.fr/
http://www.opodo.com/
http://www.govoyages.com
http://www.expedia.fr
http://www.dohop.com/

from Italia
http://www.myair.com/
http://www.meridiana.it/en/index.aspx

from germany
http://www.airberlin.com/
http://www.condor.com
http://www.flyoeger.com

from holland
http://www.corendon.com/

other:
http://www.adria-airways.com/
http://www.skyeurope.com
http://www.tuifly.com/en/
http://www.mobissimo.com
http://www.orbitz.com/