Dear Den,
you must be very cost-tolerant to tolerate what you will have to pay if you get the accomodation you decribed. Munich is VERY expensive. As far as I know, there is no student accomodation for PhD students. Are you German? If not, the university might be able to help you finding a place. Usually they don't do that. For a 30m² apartment in Munich any were kind of close (less than half an hour train ride) to the university, you can very well expect to pay at least 700 €/month, including utilities. Good luck!