Just over 2 years ago Simon very kindly sent me a new Samsung mobile phone that I've been using with my T-Mobile pay as you go SIM

Now it's started playing silly buggers! It switches itself off intermittently and starts itself up when I've turned it off for meetings at work! It's becoming unreliable and, well, just a bit old really!
As I don't use it to make too many calls (who would on PAYG) I've never considered a monthly contract, but that may be an option now.
What would be your recommendations (or does anyone have a cheap handset they want to get rid off/give away)?