When we find Karl he points out one very important bit of information. Mana stones are an expendable resource. Non mages can use them to power magical circles and devices, though both still need an actual Mage to activate initially.
So things like the food creation and house cleaning spells can be run on mana stones all over the city, though the price might have to be checked, as we're not sure how long the lower grade stones can power various spells for.
It does somewhat solve our issue with non magical residents needing mana to access magical services though. Even if the exchange rate isn't great.
