It is important to remember, if you are using the lists of private rented accommodation provided by Student Housing Services, that although they try to secure a range of good quality housing at reasonable prices, the properties have not been inspected. You should not assume that listed accommodation is "approved accommodation". You should never accept accommodation without first seeing the property. When you find accommodation you may have to pay a deposit immediately of up to one month's rent and also one month's rent in advance (always ask for a receipt).
http://studyabroadconsultants.info/articles/uk/studyukguide/living-cost-in-uk