My son has been nagging me for one of these for ages, but I've only ever seen them at £5-£6 each.
Today in store at my local Tesco Express - located in the "Back To School" ailse, these were reduced from £6 to £1.50.
They only had the right handed one, but did have blue or pink.
I then went to my "big" Tesco as I was after a left hadned one as well, but there were none at all there.
Obviously stocks are limited, but worth keeping an eye out for.