I was priveleged enough to live in areas that were pretty cheap - in Swansea and Bangor I only paid £40-50 a week rent, bills weren't much, plus £20 pw on food.
And to be more precise, it was closer to 3.5K... But still, a far cry from £12K!
When I was working a while ago I was getting £800 a month, and i managed to save £5K over most of a year, which I used to help fund my Masters. I get I'm just used to being thrifty :s