One of the conditions you must fulfil in order to obtain a visa under Tier 4 of the Points-based System is that you must hold sufficient funds. You will need to show that you have enough money to cover any outstanding tuition fees for the forthcoming academic year, and maintenance or living costs. Please refer to http://www.beds.ac.uk/international/international-student-support/visas-and-immigration/tier4adult for further information. If you are applying with dependants, this figure may be much higher.
Do I need to meet any financial requirements in order to be granted a visa by the UKVI?