Housing and Accommodation

Renting alone is stretching my budget. For those in shared houses — how did you find a roommate you actually got along with, and what did you agree on in writing beforehand?

I will be arriving next month and need a small flat or shared house within walking distance or a short bus ride of the university. Where do students actually find places — agents, noticeboards, groups? Roughly what should I budget for a first month including deposit?