In case you do not know it, there is a really sweet way to travel by car in Europe - http://www.mitfahrgelegenheit.de/
. This is a German website that is essentially a carpool-rideshare offer and request bulletin board.
Essentially if a driver is going somewhere, they post to this site, where you can then email or txt them and request to tag along and pay for a portion of their fuel costs. Primarily the site is aimed at Germany, but it works for all countries in Europe and has many options for departures from larger cities.
In a lot of cases I have found it to be cheaper than other forms of transit (faster than bus and some train) and it has many other advantages as well. You get to travel with locals, take stops when you want, and see scenery you normally would not see. Also you can post that you are a rider looking to get from A to B (Munich to Barcelona) and people will contact you if they have a ride for you. If you are lucky, you can befriend the people you are sharing with (the driver and also other ride share people) and perhaps score some free accomodation.
It is a really great service, what I would call the couchsurfing of transportation, and I wholeheartedly encourage everyone to try it for the social, economic, and other great reasons.