it can be really expensive as people have said.
As far as renting goes, it depends on where you live but one bedroom places tend to be more expensive, might be worth looking into a house share.
If your working you would also need to budget for council tax which varies depending on your area, if you live alone you get a single person discount which i think is about 20% off, if you live with students its 50% i think but again it might vary from area to area.
Again, food is usually £25 - £30 a week depending on how much you eat
then rent, gas, electric, water
you;d need to pay a bond when you rent a place and depending on the agency they charge an admin fee sometimes which can be around £75 upwards just to stop viewings and give you time to sort out the paper work. So basically befroe you even move out you'd need to spend a few hundred quid just to secure a place to live.
It's doable, but pricey, really depends how much you have saved and what your income is...