Same as you mate, I pay £10 quid for a full length of Z, which will give 3 bars so £3.33 per bar. The reason I asked the question was that I was speaking to a carpet fitter today who doesn't charge anything, just includes them in the price of the fitting.
I do that as well, buy the long ones and get 3 doors out of it....works out cheaper that way.....we must have some Scottish blood in us somewhere ...lol.......can' t see why you should do it for nowt, all takes time to do, I always drill mine fix mine with screws, make sure they don't come loose..