So i decided to make some homemade shampoo. Its fairly simple actually.
All you need is -
1 Tablespoon of baking soda.
1 cup of water.
And if you would like to thicken your shampoo just add oatmeal or cornstarch.
I think at least 4-5 Tablespoons may thicken it completely.  
You can also add some essential oils or even some cinnamon for a scent. 
Personally i added cinnamon. Smells great.
Im about to try it out, see if this stuff is as great as they make it sound.