What kind of hair color can I use at home to beautifully cover grays and last?

All right ladies, I need your help. I love going to my local Aveda salon and having my hair done to the tune of $150. But going through a divorce, going to school full-time and only being able to work part-time now, I just can't afford it. Can anyone please recommend a brand of hair color I can do at home that covers grays effectively, stays beautiful and true for more than two to three weeks and will shine? Thank you!What kind of hair color can I use at home to beautifully cover grays and last?
I've always used Excellence Creme by Loreal. I only color the roots and have to do it about every 4 to 5 weeks.What kind of hair color can I use at home to beautifully cover grays and last?
What I've always used was Revlon. I dyed my hair a lighter color, but the color didn't go against what it said it would look like on the box and it never became dingy. To help make sure it doesn't fade too badly even after a month, I suggest buying some nicer shampoos and conditioners that helps keep colored hair vibrant.