good shampoo for colour treated hair

I bought this from a salon as I was looking for something with natural ingredients to minimize further chemicals on my hair after colouring. This shampoo (and matching conditioner) make my hair feel soft from application. It does not lather an awful lot, but it does clean my hair without stripping it. My natural waves were less frizzy and my scalp did not feel super dry after colouring.
It is not cheap (for me), so I don't buy it often, but when I do it lasts a few months since I only need a small amount of the product.