Looking for an alternative to a hotel and a hostel? Berlin can boast an advanced squat culture, so take on a challenge of staying with punk and anarchist crowds. It'll be cheaper or even free of charge and will give you a chance to make friends with locals.
The punk Køpi Squat gives you an opportunity to learn practical self-defence for free, learn to play the guitar or get a T-shirt with an anti-capitalist slogan. You will definitely find shelter in one of such places, have an inside look at the life of artists or at least stay for a gig or party night.