Nearly two years ago in effort not to become a brunette (my second child seemed to have stolen my blond hair) and still pay the mortgage, I started highlighting my own hair. $12 for L'Oreal sure beat $150 (suburban Chicago price) at the salon. But now, I've found a way to slash even that cost!
I went to a beauty supply store and bought the higlighting powder and mixing lotion. (Not the technical terms). I also bought a measuring cup for the liquid and a better applicator than what I had saved from the L'Oreal kit. For about $25, I'll get 3 - 4 highlighting applications. Wow! They also sell caps where you can pull hair through if you like that method.
Now, highlighting is not that easy, and I won't say that my work is as good as the salon's trained professional but for $6, I'll live with quality difference.
Having observed my former long-term stylist over the years, here are some tips I've witnessed.
1) Highlight SMALL pieces at a time. I have found that a small circular brush gives you much greater control and a better chance to avoid huge clumps of lighter hair that would not fit a definition of a highlight.
2) Separate the sections (top, back, sides) first.
3) Put solution on the entire piece that you're working with to avoid extreme variances in color - this is not like touching up roots.
4) If some pieces are getting too light, use a wet towel to wipe off the solution.
5) Use latex gloves or have a sink of water to rinse off your hands frequently. Dry your hands before touching your hair again.
6) Don't rush - make sure you have time.
I have not used foils, but if you're that good, do it. The back is the hardest since you can't see it. I use a mirror, go very slowly, and pray. It comes out ok (front and sides are admittedly better) and I think about the cost savings.
The cost benefits are big, and I've actually been complimented by people cutting my hair on my color, so consider it the next time you want to add some sunny highlights to your hair.