Hi and welcome to the forum,
You would need to open a basic account with any bank/building society that you have no borrowing. I have heard Co-op were good and in my experience Abbey have also been helpful.
I do not have a lot of experience with pre-pay cards so therefore would rather not comment, maybe someone else will post about them.
We usually recommend once you have made up your mind that an IVA is the best way forward to stop making payments although some people like to make token payments.
Please try not to stress, you have made the first step to sorting out your finances and with the help and support of a good IP/debt advisor and other members on this forum you can find the right solution and be more at peace!
Kind Regards
Nicola
Finebridge Ltd
22 Laud Street, Croydon, CR0 1SU
0800 180 4212
www.finebridge.co.uk