£100 per week is nowhere near enough.
You'll need to be buying three to four coffees per day, preferably from Starbucks; none of this "make your own" peasant trash. The average student simply can't live on water; it has to be coffee. £50 per week, minimum.
You'll also need to buy new clothes to wear at least twice a week. Preferably something fairly high-priced, so you're always keeping up to date with the latest fashions and trends. £150 per week.
And we haven't even got started on food; you'll need to be visiting restaurants regularly (students shouldn't have to cook their own meals, do I look like I'm from a third world country?), and dipping into your wallet to dine on the finest British meats, topped off with creamy deserts. And don't forget the pricey champagne too- that's £60 per meal. Double that for dinners if you can afford it (but pretty much every student can, so cost isn't an issue here). So that's £840 per week. Breakfast? The most important meal of the day; you'll need £20 for a great, healthy full English breakfast. So that's another £140 per week.
We haven't even got to stationery yet. You'll need a new pack of pens every week, so you never run out. Forget WHSmith notebooks and colouring pencils; you need the best quality. £20 for perfumed parchment, per week, and another £10 for fountain pens. That's £30 per week.
You also need to be happy; that means, nights out with your mates. £120 per week.
Since you like to save money, I think the best thing to do would be to take a typical, cheap British taxi; £10 to get to the restaurant and then the same for the return journey. Twice per day, and then for the whole week, that's £280 per week.
So, with just the bare essentials, we're already up to £1,610 per week, not including accommodation costs. £100 per week- who do they think they are, telling us we can live on that amount?