I have natural jet black hair, about 10 years ago in my early 20s I started to get a grey patch in my parting at the front but nowhere else, since then i have had low lights highlights the works and agreed it is expensive !
I now have to do this small patch at my roots every 3-4 weeks and use that Loreal touch up permanent black its about �4 but you just get enough to do your roots,comes with little tray and brush applicator.
Stops me looking like Mortica Adams anyway :)