Why do I need different soaps?

You do not. :-) A soap can always be used for everything. A Hair Soap for the body and a body soap for hair.
However, oils and fats have special properties. For example, some have a drying effect on the hair, but have little or no effect on the skin. That's why we always choose the oils and fats carefully and mix them to give better effects to the hair or skin. Of course you could also create a universal soap. But that would only be half as good as a specialized one :-)

Why natural soap?

 
I think that will be clearer when I write down what we do not use:)
Paraffin
Isoparaffin
Vaseline/Petrolatum
Diethanolamin
Triethanolamin
Natriumdodecylbenzolsulfonat
Natriumdodecylpoly(oxyethylen)sulfat
Natriumlaurylsulfat
Polyethylenglycol
Polypropylenglycol
Benzylhemiformal
Paraformaldehyde
Bronidox
Bronopol
Glycol Parabene

Triclosan
Diazolidinyl
Urea
Imidazolidinyl
Urea
Climbazol/Antifungizid
Synthetische
Duftstoffe
Hydantoin/Imidazolidinyl
Urea
Propylene

If you don't use all of that, then why the price?

Whenever possible we use natural bio oils. Our herbs are organic only. And when shopping, we make sure that our raw materials come from the Fairtrade vendors.