Hi, I have shoulder length hair (I'm 18, and have been growing it over a year.)
It is currently a browny colour, but I want it a propper black colour. Can anyone recommend any dies I can buy (preferably online) that won't corrude my hair but will last a decent amount of time?
I did the same thing that you want to do. I had dark brown hair and dyed it black. Pretty much anything that you buy at a drug store will be good, but you might want to try one at first that washes out in a few washes. It'll say how long the dye will last on the box. Good luck! :)
Naturtint colour is good, not very expensive, and not damaging (At least as far as I've tried.) One thing you should NEVER do is use a metallic-type dye, like Grecian. They can be really harsh and drying.