I make my own skincare products and have done so for a long time. Some sites: Gorgeously Green (Sophie Uliano), Live Simply( Kristin Marr, Wellness Mama (Katie Wells). There are many others, also some good tutorials on Youtube.
I don't make hair products but I make body butters, facial serums, body scrubs and things like that. I don't buy any of those products anymore and my skin looks and feels better than it has in years.