We bought a Hamburg card from the Hamburg Underground (U Bahn). We bought one for five days that covers the two of us, and allows us to go anywhere on the U Bahn. The cost, at €59.90, is fairly comparable fo paying for Oyster cards for the Underground system in London. Like London, you can also use the buses here with the Hamburg card. But unlike London, there are additional benefits: You may use the Hamburg card to gain discounts on certain voyages on the Alster, and with the card it is free to journey on parts of the Elbe. The Hamburg card also offers discounts to museums, which, unlike Australia and the UK, do charge admission.