Mobile/Cell Advice *Probably more UK orientated*

[PizzaDrone]

So, my mobile phone network has gone incredibly expensive now and my phone is on its way out. I have my PAC code so I can take my new number with me. I'm looking for any ideas/experiences for which phone to get, that can preferably allow me to update Twitter and that, but also doesn't cost a fortune.

Thanks to anyone who can help!