The internet. Try the Home Health website. But I would try a cheaper brand if I were you. With clearblue you are paying for the name and the packaging and if you look on that site, or amazon, you will find plenty of other tests that do the same thing for a fraction of the price.
As dotty says Amazon appear to be the cheapest for the digital (smiley face) ones! I did not get on with the cheaper types but have always got a positive on the digital ones using them in the morning! HTH
thanks for the advice, ive been using the cheapies but have trouble telling if the test line is darker than the control line, so i might plash out on trying some digital ones, if i don;t think much to them i won't bother again with the digital ones,