I have a nokia 3200 and am on vodafones ready to go, but just wondered when I see phones advertised in both o2 and vodafone shops, can you buy these and change your sim card and does it work????
Technically you could just swap out the SIM card and the phone should work. As far as I know the phone companies only 'lock' the 'pay as you go' handsets.
However, you'll probably find that to obtain one of the heavily discounted phones that are advertised, you need to sign up to a pay monthly contract for a specified period of time. Therefore you will be paying for the duration of the contract whether you use the phone or not.
Technically you could just swap out the SIM card and the phone should work. As far as I know the phone companies only 'lock' the 'pay as you go' handsets.
I don't think this is true.
Subscription phones are often locked (or certainly used to be) as well so that you have to keep the phone for the initial contact period. I think the operator will unlock it for you after the contract period is up.