When can i buy iphone 5 as pay as you go?

Because every phone shop seem to have it on contract and online says it will take over a month.
please tell me

CeX if you're in the uk. You can buy online or in store, their website is www.webuy.com. X

You can fing sim-free iPhones from Amazon - http://www.amazon.co.uk/...lias%3Daps