Best hair dye that you used?

I am very nervous when it comes to my hair and dye. I never dyed my hair and have noticed a lot of greys. So i went to my hair dresser to get advice and I didnt even have to dye my whole head they just covered the greys. I would never use anything out of the boxes because the color never comes out right, all the box colors have matelic in it... not cool. Hope this helps.