Ive not really found a problem with cathedral courts kitchen size!cosy and sociable in my experience!
Some of the main costs ive found to be:
Accommodation - in cathedral court it is 80.35 a week
Food - i tend to spend about £12 on averge per week at Tescos (depends on your tastes, appetite etc obviously!) There is also a fruit and veg market weekly, which apparantly has cheap fruit and veg (than tesco)
Laundry! - 1.80 for a wash, 20p for a dry (usually takes two dries)
Going out - buy tickets early for the union, could be a few £ cheaper, definitely drink before you go to the union though, as drinks seem to be fairly expensive! cant comment on going out in Guidford town though..as still yet to experience this
Gym - not a major expense weekly but: basic membership is £65 for the year (is basically insurance for any clubs you join) then e.g.gold membership - add £30 and you can go to all classes and obviously use the gym. clubs are usually £10 yearly membership on top of the basic £65... if all that makes any sense!