Diablo 4 - Uncertain Seneschal Stone Cache's costs are tied to your character level!

One of the Chapter Requirements is to collect 50 of these. At Level 100, these cost 400 shattered stones apiece. But at Level 20, they only cost 200 stones.
The good news is, you can buy the caches with your lower-level character, and open them up on your main character, and collect the stones. This will save you up to 10000 stones in crafting costs.