This is how to dye your hair lavender!
My hair here is a very faded lavender, but regardless of what colour your hair is you can still do this!
I bleached out my old colour, and my bangs had already been super white so when I removed the lavender they turned a lovely colour! I however had some problems with my bleach, I used a blue based bleach and my hair took the blue and turned green in spots, but that isn't much of a problem because if you check a colour wheel purple/lavender is basically opposite to green/yellow so it will cancel it out (In theory..)
I used three boxes of Color Brilliance Ion hair dye from Sally's in Lavender.
Grab a bowl, some gloves, and a hair dyeing brush!
And some conditioner, it doesn't matter what kind you use (I believe white is preferred although mine had a green tint to it),
Pour however many boxes of hairdye you think you'll need into the bowl, then add as much conditioner as you think you'll need! Combining the two lowers your cost on how much dye you need to buy plus it conditions your hair while you dye it!
I left it on for probably an hour, and this is the results! (I do have hair extensions in, my hair is just past my shoulders and this made more than enough for it!)
TAAADAAA, I hope you enjoyed my tutorial on how to dye your hair lavender!