Best permanent at home kit for Black

i have medium brown hair. a couple weeks ago i tried to dye it black at home using loreal feria black leather. i have VERY long hair. i didnt get it all dyed and i didnt use all the stuff in the bottle and i dont think i left it in long enough.. anyways my hair is more of a mix between dark brown and black now. i want to redye my hair this weekend since it will be the two weeks i had to wait to redye it. or maybe next week. but i wanted to find out with kit would be the best. i mean, permanent, last the longest, looks black not brown ect....
i dont have enough money to go to a salon but i would if i did.
and if at all possible, is there a permanent dye black that instead of red or blue undertones has purple?
otherwise, just the best black home kit.