Overall, most students need around €1000,- a month for a living, the rental fee for accomodation included.
For the whole semester, you will have to expect additional expenses of €100,- for Books and €50,- for other material as well as the semester fee. In Germany, every household also has to pay a monthly broadcasting fee.
Dormitory rooms usually cost between €250,- and €300,- per month.
Rooms on the general housing market can cost up to €600,-.