I went to Robben & Wientjes to rent a van for the Schlafsofa. The girl at the desk asks: Are you Canadian? (I am speaking in German.) I say No, American, but I have a British passport and driver's licence (they require a driver's licence valid in the EU). She gives me a reservation for 10 am and tells me to bring 100 euros in cash for a deposit.
R&W is a car rental place that will rent a van out for an hourly rate of 3 euros.
She asks when I will be bringing it back and I say Höffentlich um 11 Uhr. I am renting a slightly larger van which costs 4 euros an hour.
Berlin (or rather Germany) has two other facilities that make life easy for the footloose. It is possible to get a Post Office box for the price of a 15-euro key deposit. (Yes. Really. There is no charge for use of the box.) So if you are moving from one short-term let to another, as I did for my first two years, you can have mail sent to the PO Box. You can also get a free Packstation, which accepts DHL deliveries. If you think you may not be home to take deliveries of packages, you can have them sent to the Packstation. You have a card with a PIN; you go to the Post Office to the bank of Packstation boxes, type in your PIN; the display directs you to the box where your package is waiting. This section of the Post Office is open 24 hours a day.