I want to dye my hair purple?

I used that Raw Demi-Permanent Dye from Hot Topic and i hate that didnt work at all, now i use Manic Panic brand they dont have any chemical in them, their colors are nice and beautiful, i had Violet color before its really pretty, they have nice purple color too, last year i mixed hot pink with shocking blue together it turn to a nice purple, the bad thing is they wash away after 2 week and you need to dye it again, but dont worry use as much as you want, nothing to damage ur hair. have fun :)