Why is the cost the same since potions are more versatile (can be used by anyone) and scrolls can generally be used by caster types that require the spell to be on their spell list? Should scrolls be slightly cheaper to create?
Should certain spells be unavailable as potions? I’m thinking specifically Restore Life & Limb here, but others might fall into that category. I’ll probably make RL&L a non-potionable spell in my campaign, but I’m interested in hearing others’ thoughts on it. It just sounds kind of ridiculous having a potion dumped down someone’s through to revive them instead of a Cleric casting it from a scroll. But, we’ve had people use potions on “mortally wounded” PCs to get them up to 1HP, so …
The effect of the potion is always triggered on the drinker (or, if an oil, on whatever the oil is rubbed on).
A potion cannot be an instantaneous effect.
A potion always has a duration of 1d6+6 turns.
A potion cannot be used to record a new spell.
Scrolls:
The spell has its usual effect and duration.
Any type of spell can be put on a scroll.
A scroll can be used to record a spell for later conveyance.
Many spells can be recorded on one scroll, so encumbrance is much less.
As far as a potion of restore life and limb, I’d say no, but I’d probably permit an Oil of Restoration. The idea of a holy ointment that can be rubbed on the body to restore life or re-connect a severed arm makes sense to me.
Cannot be layered—stacking potions results in three turns of paralysis.
Only affect the drinker and have a (default) duration of 1d6+6 turns.
Scrolls:
Can only be used by a limited group.
Can be layered.
Function exactly like casting the spell.
What this means is that, in general, potions are particularly useful for some classes of effects, and scrolls are particularly useful for other classes of effects.
As an example, potion of polymorph is the best way to give the fighter some dragon-transforming abilities . . . but a mage who wants to polymorph gets better duration and the ability to end the effect at will when using a scroll of polymorph self.
Let's clarify, then, that a potion can't have an instantaneous effect on something other than the imbiber. I.e. you couldn't drink "a potion of fireball" to get the ability to unleash 1 fireball.
You could certainly do that in your setting, but if you did you would be changing the core assumptions (spelled out in more detail below) that justify the pricing of scrolls and potions.
But, you could say, research a new potion called “Potion of Firebreathing” that uses the Fireball spell and allows the imbiber to breath flames within the next round or something?