As anyone who regularly does VW knows, void stones are gone very quickly. (Natural regeneration of void stones isn't very much at all.)
Currently, 1 void dust on my server costs around 30k gil.
I think there should be other ways to increase your stock of voidstones.
I've thought of a few potential ways to increase void stone stock;
- Purchasable with cruor
- Increased rate of void stone regeneration (Maybe a system that if you're under a certain amount of stones, you regenerate them faster until you're at another amount)