The most economical way of getting around Berlin is the public transport system. The overland routes are covered by the S-bahn and train, while the subterranean routes are known as the U-bahn.
There’s also a tram, which is probably the first type of transport you’ll see when you arrive in Berlin. Its three types allow you to transfer from bus to U-Bahn to S-Bahn and tram with a single journey ticket. The metro system (U-Bahn and S-Bahn) operates Mon-Fri from around 5am-1am and all night at the weekend.
A single ticket costs just over 2 Euro, or get a day pass for 6 Euro. For multiple days, a 7-day ticket is 26 Euro approx. The Berlin WelcomeCard does just that, including transport across all networks as well as entry or discount for many tourist and cultural highlights, such as museums. This multi-network transport map is handy for planning your journeys.