^^I use the chroma treatments (they come in the little pink tubes) at home and I love them. I have never purchased Kerastase through *bay though, I would be very careful when purchasing bc I know Kerastase has lots of problems with people selling "knock off" products.
I sometimes buy their products and use them at home instead of going to their salons and pay a lot of money. It is worth it. You just have to know what is good for your type of hair. I usually buy this one: