What is the best hair coloring product for men?

I keep my hair short on the sides so i need a product that I can buy and be able to use a couple of times. If I buy just for men they give you one application but I end up wasting so much. Plus it doesn't work all that great on the sides of my temples. I still see gray hairs. Can anyone tell me of a good hair color product that won't leave any grays? maybe one for women I'm not sure. Please provide links if you can thanksWhat is the best hair coloring product for men?
i just use food dye. works good and it is so cheap. pink is easy for me because i have premature white hair. last month, it was blue.