Which inexpensive hotels had you stayed in Europe?

We all know traveling to Europe is not cheap, even if some believe it is. Anyway I want to know differnt options of affordable clean bed and breakfasts or hotels in the following cities if any of you had travelled to those cities before and remeber the name of the accomodations. Im travelling in August to Europe with 5 more people ( 4 cousins and one friend of all ) and i have to be in charge of looking for the accomodations and see what the other think. We are not backpackers let me tell you but we can't afford expensive fees either. At least clean rooms, breakfast included if possible.

Cities: Venice, Berlin, Munich, Madrid, Prague, London.

Thanks

Which inexpensive hotels had you stayed in Europe?
Post Opinion