Where to get the raw materials? In the north of Europe there are interesting stores to buy raw materials for natural cosmetics like these German ones:

https://www.behawe.com shop, that you can also consult in English or French. Also, the skincare shop, although this one, unfortunately, you have to try to understand it in German: https://www.skincareonline.de or also https://www.cosmopura.de. And this one too: https://www.rosarome.de
In the NETHERLANDS:
And also the dutch www.jojoli.nl store that distributes its products also in Belgium and Germany.

If you live in the Netherlands and understand a little French, I would also try the AROMA-ZONE store because it ships its products all over Europe at very competitive prices and they have good quality.
If you live in the UK, maybe, you can give a try to https://www.aromantic.co.uk

In the naturallythinking store, they also have ingredients for natural cosmetics: https://naturallythinking.com
Also in this one: https://www.baldwins.co.uk
This one is special for big quantities: https://allinpackaging.co.uk
Some very specific products, such as “light mountain color the gray” dye or, perhaps even, grapefruit seed extract, you will only find them with an interesting value for money-shipping costs on the page of https://en.iherb.com