Hair Dye

I just bought some hair dye so I can do it myself but I have a problem, Im trying to get it as close to my natural color as possible, I bought a color that looks like it would be alright, I have a medium blonde color on the ends but 3 inches of my regular dark brown for roots, I want it all to dye the same color and not have half of it be light brown and the other half dark. Does anyone have any tips? I would go get it done professionally but im all out of money. I would really appreciate it if someone could help me out.

Thanks.

If you hair is a medium blonde on the ends and a dark brown on the roots, you can dye it dark brown with no problems. The medium blonde color will probably turn out black and then will fade to the dark brown after a couple of days. Since your pigment was removed by dying/bleaching it medium blonde, when you go to add the darker color back, your hair will be screwed up and just go black.