Use any unlocked 3G phone for your 3 sim card and you will be up and running with £10 worth of calling or text credit for just £9.99.
With 3's Flat12 tariff you you pay just 12p for your call per min or each text there is an added bonus that your credit does not have an expiry date. Voicemails are free and you can even listen to you voicemails if you have run out of credit.
With your credit you can buy a Stretch Add-on and you could double the minutes that you would normally get for your money. You can also get an Internet Add-on with your credit, which will cover all your internet access for just 50p a day or £5 per month.