I made some soap recently and have been testing it as shampoo. The formulation I have isn't great as shampoo, my hair gets pretty greasy if I don't shampoo again every two days.

That being said making the soap myself was pretty easy if you want to try your hand at it, just find a recipe that's meant more for shampoo. I would suggest looking into using the hot process method so you don't have to wait 6 weeks for the soap to cure though