20 year old boy, looking for accommodation in London

Hello, my name is Carles. I'm a student in the University of Valencia. Next year I will be studing in London, in the UCL. I will be going along with a girl who's studying as well in my university. She is studing in the UCL as well next year. We are very organized people. I would like to look for some kind of apartment or maybe shared rooms because the student houses and residences are pretty expensive. We will be doing a full course of ten months. We are looking for something whith a reasonable price and not far away from the UCL if it's possible. We would arrive in september.

Really looking forward to find a nice place to stay in London. We will be thankful with the help you can give us what we need!