Any cheap Casio will be fine for years, here's a decent looking one for £15 delivered;
https://www.amazon.co.uk/Casio-Coll...sr=1-70&nodeID=328228011&psd=1&keywords=Casio
If you don't mind digital i have a F91W from about 6 years ago that's still running and they are less then £10 delivered.
Tonyuk
https://www.amazon.co.uk/Casio-Coll...sr=1-70&nodeID=328228011&psd=1&keywords=Casio
If you don't mind digital i have a F91W from about 6 years ago that's still running and they are less then £10 delivered.
Tonyuk