In a homebrew campaign I'm running for my seven players, I was looking to introduce a limited amount of consumable weapon buff items that add elemental damage, not unlike the Pine Resins from the Dark Souls franchise.
Essentially, the effect would be something along the lines of "Applied weapon deals an additional 1d8 (Element) Damage for 10 hits/1 minute". What I'd like to know is for this ~10th level party, what price would be reasonable for such an item, were they to want to purchase more?
Here's my reasoning: I would assume the price to be in the low-mid hundreds. Based off of Elemental Weapon, when cast at 5th level, is a bonus action spell lasting up to 1 hour, granting the weapon an additional 2d4 of elemental damage and a +2 magic weapon modifier. It can only be applied to nonmagical weapons however, requires concentration, and requires a spell slot. The consumable I had in mind would require an action to apply, deal, say, a base of 1d8 elemental damage, last for, say, either 10 hits or 1 minute (whichever comes first), and does not grant the weapon a +2 modifier on attack and damage rolls. I would, however, be applicable to magical weapons as well, since I see no reason otherwise.
Using Sane Magical Prices, I would presume the price would be similar to the difference in cost between a 5th level spell scroll (Upcasted Elemental Weapon) and a 4th (+2 Magic Weapon) to get rid of the +2 modifier, which comes out to around 320gp. This does not take into account the huge difference in potential duration, the lack of required concentration, or the possibility that the spell fizzles when being cast from the scroll.
This is where I've kinda hit a wall: How would these factors impact the price? Thanks in advance, and have a wonderful day!