Some bargain sulfate-free shampoos include Palmer's Coconut Oil Formula Conditioning Shampoo, Finese Clean, Nature's Gate and L'Oreal's EverPure system. All these brands cost under $6 as of 2015.
Sulfates such as sodium laureth sulfate and sodium lautyl sulfate are the compounds that create the lathery foam in shampoo and other cleaning products. There are some theories that the sulfates in shampoo strip the hair of its natural oils, fade color faster, and can irritate the scalp in some sensitive individuals.
There is no hard evidence that sulfate-free shampoos are better for a person's hair or health. However, some hair dressers believe that sulfate-free shampoo is superior based on anecdotal evidence.