If it's past 200k market price, it's an artifact.
So... Priceless!
Aye artifact, be wary of giving such things to mortals lest it bust your game ;)
I think the point they are getting at is that this item may possibly be valued at 200K+ GP... and that makes it an artifact.
Allowing any 9th level magic spell to be used at will forever is artifact level power in my opinion.
The closest magic item in the CRB is a mirror of life trapping. That basically allows a 9th level spell to be used at will... but there is a save for the effects and there is a practical limit to how often it can be used at 15 times before you recycle targets. This item is 200K and I think having Shapechange at will is more powerful then this.
But if you want a price, I would go with a list price of 540K GP X 5 for a total cost of 2.7M GP. This is the formula you used above with a five or more times per day multiplier. You could also use the old 3.5 Epic book to get an alternate price setting with DM approval.
Why do you want to know a price for this item? That would help come up with approximations for your purposes for a priceless item.
I did answer what I thought it was worth. I think the value of the item is at about 2.7 or maybe 2.5 million GP. The multiplier is for a couple of reasons. Continuous effects of spells that have a shorter duration are more then the base calculation and have a multiplier of between 1.5 and 4. Also items that are of greater value and usefulness then standard for their level are more valuable. (Such as a ring of invisibility or cloak of displacement.) My estimate was a X5 final number.
Going back to 3.5 rules - Bracers of Relentless Might gave a +12 Bonus to STR and Con. These items had a value of 4.4 million gold. Your shapechange spell may not add as much to either ability as that but it will be close to that number to STR and CON, plus NA and various powers and abilities. So pricing an item at about half that value is a pretty generous price I would say.
It is of course up to the DM and level of expectations for your game and table as to what anything is worth. Not every group follows the wealth by level rules. (Mine does not as we are about double those values.)
First off the spell is much more powerful than the PF version of polymorph, so in effect it is higher than 9th level in PF "world" if you are really interested in a true price comparison. Higher than 9th level is epic, which should carry a huge price tag.
There is a multiplier for an item when there is a # of times per day that I'm guessing Thazar is tacking on. Normally I would just toss the idea of it, but honestly the ability to use a better shapechange than the PF normal by anyone/any class as opposed to what a caster can do at max level... Well the price deserves the modifier in this case.
It's a 9th level spell. I'm not interested what level it is in "PF world", because I'm playing in "my world".
Then set the price to whatever it'll be in "your world" and be done with it.
Or, since it's an artifact, make some big epic quest to get it for free.
What you are doing is like taking a volkswagen beetle, and demanding to know the steps to make it into a space shuttle. There are no steps. It's not a space shuttle. The rules of space shuttles do not apply since it is a car, not a space shuttle.
Mods: Flagged for changing forums, as this is homebrew.
And when a "reasonable" price is given by several posters you disagree. So the only thing left to do is say "do what you are going to do anyways." You are essentially asking for help and when it is offered saying "no, I don't want to hear it" because it isn't the answer you want to get.
This item is pretty much the definition of an artifact, an at will ability that is better than a comparable 9th level spell... without a drawback. Heck, it is better than an artifact.
Unfortunately you are talking about a non PFRPG spell, it really had no buisness in the PFRPG Rules Forum in the first place.
Your best bet would be to sit down with the GM and work out a price. If you are the GM, time to make a command decision.
I am asking for advice. If anything, the thread should probably be moved to Advice subforum.
If it would be so easy to make a decision, I wouldn't have made this thread.
I'm almost sure it's worth more than 540k, but 5 times more is just too much.
you can ask for advice in the homebrew forum there's no rule against it
But I'm not homebrewing.
Infinimorph is a homebrew spell which follows alternative Polymorph rules homebrewed by The Giant from GitP.
Errr K ;)
Creating and pricing magic items that are not in the core rulebooks is a homebrew topic, regardless of the spells involved. Using a homebrew spell only makes it more so.