You have to phone Orange to get this deal for existing Orange PAYG customers and ask for a deal on the San Francisco as you are already a customer. They should offer you a £30.00 discount. The cost is £79.99 which includes a £10 top up card.
0800 079 2000
I signed up to Orange 2 years ago to get a free sim for Orange Wednesdays and used this account to get the deal (i use this number once in a blue moon for Orange Wednesdays and have only topped up once in 2 years).
I have unlocked the phone to O2 easily and for free over the internet and will use the £10 top for another year of Orange Wednesdays :)
Great phone at a great price!