Your goal seems to be to have the NPC profit every time it is cast. It looks like you value spells without material components, but why not embrace (expensive, consumed on use) components?

The easiest way to charge someone every time they cast the spell is to build the spell with a material component you have monopoly over. This is something the Wizard can do himself at any level, and will fall within/sidestep the legality concerns by having built in rights management (punishment is irrelevant if it simply doesn't work without the requisite consumed-on-use license token).

Your goal seems to be to have the NPC profit every time it is cast. It looks like you value spells without material components, but why not embrace (expensive, consumed on use) components?

Instead of making and selling scrolls, the easiest way to charge someone every time they cast the spell is to build the spell with an "expensive" material component you have monopoly over. This is something the Wizard can do himself at any level, and will fall within/sidestep the legality concerns by having built in rights management (punishment is irrelevant if it simply doesn't work without the requisite consumed-on-use license token).