Does anyone recommend or not recommend a do it yourself hair coloring kit at home? I keep seeing all these commercials and ads for a new mousse one that seems so easy to apply.

I have no gray hair...just brown hair with grown out summer highlights I'd love to cover up. My hair stylist wants me to come in for lowlights and highlights in more fall-like colors and honestly with holiday shopping coming up - I just don't have the $ to spend on my hair right now. Really need to do something about my grown out highlights though.....

How do I even know what color to choose? I don't want to go too dark.

Any tips would be appreciated!
Also...it washes out eventually right? None of it is permanent???
I'm totally clueless on hair coloring...all I ever do is like 10 foils of highlights ever summer and that's it.

TIA!