A box containing two hand warmers are now reduced to 79p
Snap the metal stud in the gel and wait seconds for it to heat up to 55 degrees C. and it stays hot for up to an hour. Pop them into boiling water to refresh them for next time. Can be refreshed up to 1000 times. I got mine at the Bexhill, East Sussex store.
Done a quick search and found similar starting at £2-3 going up to over £6