new payg mobile

Hi my wife's old Ericsson A1018 coca cola phone has given up the ghost(got
wet) and she wants a new phone. All she needs it for is to call me to go and
collect her from wherever she is, but she has decided that she also needs a
camera phone as she was away for a girlie weekend and missed out on some
blackmail material :-).

So what is the longest battery life between charges phone with a camera,
since it will spend days in her handbag switched off (she only ever switches
it on to make a call) and preferably quite inexpensive? And preferably
unlocked or easily unlocked.

The present one to one sim or whatever it is called now is unharmed (tried
it in a friends phone)with about £6 still on it. Not bad for an initial £10
over a year ago. Shows how much she uses it.

Thanks Ron