Planes, Trains & Automobiles
Well, I know that trains & busses (fun!) have already been recommened for your European voyage, but I would like to make a unique and new suggestion---a plane. EasyJet is an awesome company that has planefares from about $40 dollars. (From London to Barcelona, for example is about $51.99). EasyJet is, according to a friend of Norris's, very cheap and low budget, so don't expect anything too plush.
----Livvi'i