Can I get a mobile PAYG SIM card in China to dial the UK?

[Joker]

first you need to buy a SIM card, which is free itself, but you need to top it up, just add 50yuan or 100 yuan. Then you need to buy a IP card for calling or texting a UK subscribe. Buy a 50yuan or 100yuan card. You can either use this card on your mobile or in the telephone booth. It has a account and password.
how to:
17909+44+area code+number
it charges like 0.5 yuan per minute, which is super cheap.

[Charlie Brigante]

I'm going to China in a few days and was wondering if anyone knows of a cheap PAYG sim card that I can buy while i'm out there to allow me to send cheap texts and calls to the UK? If you know of such, where can I get one from (airport?) and how much are the rates?
Thanks