To get by comfortably, a good rule of thumb is to go by twice what you pay in rent per month. This should cover food, bills, travel, and one-off expenses. You can get by on less, even without a job - in my 1st year I lived off £15 per week for everything except rent. However, to allow her to go out and have fun, I'd say nearer £30-£40, and maybe a bit extra at the beginning of term for books and initial shopping.

Daisy