Go here to get a free Virgin sim card.
http://www.virginmobile.co.uk/promo/duoSim.html
I got one a while ago that had a fiver on it.
I barely use a mobile phone (hand me down from my daughter), except for the odd text, I keep it in case of an emergency in the car, and as alarm clock.
Oops, you need a phone as well, maybe someone has an old one they could give you?