Where can I get it for that price.You could weigh it out on digital scales or alternatively measure out a tsp into 4 litres (after all it costs less than £3 for 500ml, about 6p as tsp).
I've just been round to the local chemist.
They have a 5ml spray for £2.50.
250 ml 4% at £16
500 ml 10% Alcohol solution for £18