Tips for a student going to Europe?
conorh: For free accommodation I recommend couchsurfing.org. It might be a little tricky with 3 travelers, generally people have couches for 1 or 2 people, but all of those cities will have lots of couches available. I have hosted lots of couchsurfers (highly recommend this if you can do it) and I've couchsurfed in other countries, never had a bad experience. When you are staying with someone living and working in a city you will have a much different experience than if you are staying at a hostel or hotel.