You dont need tons of different colours, and if you buy a paint set, the instructions are a bit misleading that come with them, so dont be dissapointed if what you get doesn't look like the pictures on the guide, I only use three / four colours and then create blends using those ones to get the different shades, lots of painters on here and most have our own way of doing things. YouTube is also very handy. Myself, I use Vallejo Brown sand 70.876 - Base. Basic skin tone 70.815- highlights. Black Red 70.859 - Shadows. They all need to be of a milky consistency, so two to three drops of water mixed in.
Base Brown sand
Highlight 1 Brown Sand - Basic Flesh 2:1
Highlight 2 Brown Sand - Basic Flesh 1:2
Highlight 3 Basic Flesh
Shadow 1 Black Red
Shadow 2 Black Red - Brown Sand 2:1
Shadow 3 Black Red - Brown sand 1:2
For a lighter skin Tone, i replace the base colour