I used my Swedish bank account and card the entire stay and it was fine,
just tell your bank that you are going abroad so that they do not block your
card, you can usually do it on their webpage. For transfering money to an
English bank, to pay rent and other bills, I used transferwise. They charge you
some little percentage of your transfer and works really well and fast.
Living and traveling
Living in London was expensive, rents and travel costs are higher than in Stockholm. The Erasmus scholarship covered the added cost for rent in mycase. Too keep the rent at a minimum you can live in the outer zones of London but then you have to pay more for traveling, check out traffic for London’s homepage for traveling card (oyster card) prices in the different zones. I lived in zone 2 and travelled about 40 min to the university, so I for me it was cheapest to buy a monthly oyster card, if you live close to the university you can save money and instead have a top up card when you pay only for the distance you travel (still more expensive than Stockholm.). To get the students discount for oyster cards you have to apply to traffic for London, it takes about a week so do it as soon as possible! I considered buying a bicycle while in London but soon realized that the traffic was not at all accustomed for bikers and more aggressive than the traffic in Stockholm, not to mention- on the wrong side!
Eating
Food at supermarkets are approximately the same price in England and Sweden, except that Quorn (vegetarian) is much cheaper in England and a good way to save some money on food. There are a lot of farmers markets in London that you can visit to buy locally produced food and drink to reasonable costs. Eating out in restaurants in London often comes with a 12.5% service charge; make sure to look for it in on the recite so you don’t tip twice.
Sights
One of the best things about England is that most of the museums and sights are free of charge. However, some of the more popular exhibitions at the museums are not, but students often get a discount.