When I was there, a hotel room was $2.50 per day. I also stayed at aWow. I would never want to live again in the US but if I had to I can think of a couple of American cities I might consider. As far as Europe goes there are several cities I'd rather live than Berlin but I'm sure you have reasons why you like Berlin better than any other city.
Mansion that cost me $1.50 per day. There was so much to do I spent a month there.