Dossing in London
If you do already know people in London then do your best to get them to let you stay with them for awhile. 'Dossing' is very common in London and is a cheap way to find your feet in the city without having to pay a fortune. Not everyone will be keen to accept dossers and, depending the kind of house your friends are staying in, you might only be allowed to stay a few days. My house was very dosser friendly, allowing people to stay for as long as they can stand, having as many as 4 or 5 at one time, and charging £5/night for the priveledge of getting a mattress in one of our out-of-the-way dossing rooms. It can be a pretty sweet deal and some people would stay for months waiting for a bed in the house to free up. It's a great way for a big sharehouse to get extra money for parties and household items as well, so it works well for everyone.