Reeeka - We are going to be living in Bristol and found a very cheap one bedroom furnished flat. This is the budget that I drew up for my visa application (that I had posted in a separate thread about the spousal visa and money):
Rent - £475
Council Tax - £38
TV license - £11
Gas - £30
Electricity - £30
Water/sewer - £27
Telephone - £25
Transportation - £130
Groceries - £152 (£35/week)
Household items (toiletries, cleaning supplies, paper products, etc.) - £40
Pets - £25
Personal Care (like hair cuts) - £20
Total Monthly Expenses - £1,002
The rent, council tax, and water/sewer are based on the actual rates for the property we are renting. Transportation is based on buying 2 monthly bus passes for both zones in the city. Everything else is an estimate based on what I could find on this website, what I remember us spending 5 years ago, from talking with the ILs, and from doing online "shopping" at sites like Tesco.com.
The budget doesn't include general spending (clothes, dining out, entertainment). And it doesn't include any money left over for savings - for emergencies, or holidays, or gifts.