I went shampoo free last year and being a girl, it has saved me a bundle on shampoo and conditioner.
What I do is mix a few tablespoons of sodium bicarb with water,pour slowly over dry hair and massage in,then rinse off thoroughly - this cleans the hair and scalp, leaving on the natural oils in the hair. Then a couple of tablespoons of apple cider vinegar mixed in water, and massage into hair bur not scalp - this conditions the hair and makes it easy to comb/brush- again rinse it out well. (don't worry, once dryit doesn't smell of vinegar).
My hair (long dark curly) has never looked better. The hair initially goes through an 'uncomfortable' stage for about a month while natural oils (which shampoo strips) return to the hair. Once through the transition stage, hair looks clean and glossy, never smells dirty or like it used to, looks lank and gross three days after shampooing. Even after a week with just a quick rinse and brush every day - still looks and smells great - I just clean with the bicarb and vinegar solutions as needed.
I now look at shampoo and conditioner as a con - once you start using shampoo and conditioner, you're tied to using it and paying for it, otherwise oils are overproduced making the hair look horrid. Most people don't get through the transition to shampoo free, because it does take 3-4 weeks for the oil production to normalise to what it should be.
Just thought I'd share.