PC on material rices

Hello.
I really need to know what price should materials be sold/bought for.
In particular: Tanned hide squares, scales, jadeite shards, monster fangs.

I know the prices constantly vary, but I would like to know how much those materials should be bought/sold for in %.
In other words, for how much % of the shop price shouls I buy/sell those materials?
They percentage probably chages between the listen above materials, so could you please give the percentage apart for every one?

Thank you.