The simplest way to find a room or an apartment is to search on the private housing market. Many students in Berlin live in shared apartments (WGs) and there is a relatively large supply of rooms. You find these offers on the internet, in various Berlin magazines, or on notice boards in different places of the university. 30 minutes to one hour commuting time on public transportation is nothing unusual - depending on where you live in the city. It is advisable to attend to find a room in Berlin soon because low priced accommodations are rare.
Rents in Berlin normally start at 250 Euro, shared apartments tend to be less expensive. On signing the lease your landlord will probably expect a deposit of three months, reimbursed with interest at the end of tenancy as long as nothing has been damaged. Sometimes a commission or a compensation for furniture is requested; therefore, make sure that you bring enough money with you.
If you arrive in Berlin and have not yet found an apartment or a room you will need cheap short-term accommodation at either a youth hostel (in German) or a guest house (Jugendgästehaus).
Within 10 days after your arrival in Berlin, you need to register at the local authorities (even for a temporary stay). The proof of residence registration is needed to open a bank account.
The Berliner Bürgerämter (in German) are related to the particular districts.
For the registration you need to bring:
All students from EU Countries, Iceland, Liechtenstein, Norway, and Switzerland ask for the "Freizügigkeitsbescheinigung", when they register at the Bürgeramt.