Where in the world are you .. that’ll effect things.
Do you just want to teach a lesson, help cover utilities .. or want a contribution to all the other stuff too.

I’d look at what your more local (even if that’s 100miles away) Universities charge for their halls as that’s utilities included .. if you wanted to go the whole hog look at catered accomodation rates.

12 years ago for me in Central London , catered halls, (1 meal a day weekdays, 2 meals a day weekends), cost me £80 a week! must be more than that now.

Or when I was earning that amount on the south coast my share of rent alone was costing me £60 a week in scuzzy, non C/H 1 bed flat shared with the mrs) then bills on top