Do what I done. Get a basic nokia from Asda. £10/15 and a payg sim. Calls 8p per min, texts 4p. So long as you remember to keep it on silent in case an inpatient WG decides to call or text?
I also got an Alcatel pixie4 android from Tesco for £20. However, as I find android phones confusing, with so much stuff I don't want anyway, gonna chuck it. My normal non punting mobile is also a basic Nokia. £10 per month with Virgin Mobile, 100 mins, 100 texts.