I was looking at them recently - I noticed that beauty express sell them at about £25. It is not very clear if it is for a pair or not, but if it is then it is a very good price I think. Normally they are about £50 for a pair.
Beauty Express 0845 702 3803
Also try Cornwall Hairdressing Supplies in St Agnes - speak to Trevor as he is really getting into nails and has increased his lines tremendously ( please tell him I told you!) if he doesn't have them he will surely track them down & order you some and he is very keen on prices. 01872 572116