I just thought I'd share this with you. It could well be that you know this information already, but some don't.
If you buy a £1.00 sim through Quidco you get £20 cashback, so that's £19 profit.
If you are on orange dolphin you don't just get free access to Facebook, Bebo and Myspace but to the whole of the internet.
I have had a sim since January and I confirm that I surf on my phone often and don't get charged. Just make sure you top up by £10 a month and you'll get 300 free sms and internet access. On orange website they say you can use up to 50mb a month. Not much but if you don't surf a lot just occasionally when you are out that should be enough.
For more info read: http://www.cableforum.co.uk/board/65/33642936-orange-dolphin-plan-free-gprs.html
So if you top up £10 on dolphin you get:
300 sms a month to anyone
The £10 on the account could be used to call other mobiles (so 50 minutes worth of calls), or choose orange magic numbers (20 p per call), in which case 50 calls. Or buy an extra, etc....