My group is trying to figure out what the item creation cost to make a ring of magic aura would be. One of the characters wants to mask their class and abilities with deceptions such as wearing a "magic ring" to explain one of their class powers, to make everyone else think it is the ring generating the "spell"
Could someone please assist us with figuring this out? Thank you.
I'm not 100% clear on what you're aiming to do. You want the ring to seem to be magical, and you want the special effects that happen when the character casts a spell to seem to emanate from the ring, is that it?
The base spell to make a ring seem like a magical item of a type you choose would be Magic Aura. A continuous magic item with that spell, according to the base formula, would cost 1000 gp (500 to create) and that seems reasonable to me, particularly since the ring won't actually do anything but appear to be magic.
It would take a fairly detail examination, along with a successful will save (which wouldn't be terribly difficult to make) to reveal that the ring was a fake.
That being said, how well someone would be able to pass off their own abilities as being an ability of this ring would depend greatly on what was trying to be emulated. If, for example, every time your ring cast fireball you had to pull out some bat guano, say a few mystic words and make arcane gestures with your hand, people might get suspicious.
The idea is that a Cryptic would pass off their Disrupt Pattern ray as being generated by the ring, because they're acting like a simple rogue instead of someone with psi powers.
All the powers they are taking are mostly undetectable self buffs, enhancing their own senses and such. Noone in the party knows that the character is anything other than a rogue as a Cryptic has most of the rogue class skills as their own class skills.
Well, the player has an advantage there, because as far as I know, Paizo has never published anything concerning how to identify a supernatural ability. Assuming you don't want to change that in some way, then other then a detailed examination of the ring, the method would work.
Anything like arcane sight would still determine that the character themselves had spellcasting/psionic abilities however. I am not 100% sure of the psionic rules from dream scarred press, but the Pathfinder standard for spells is that even they are buffs on yourself, unless you have a specific ability that lets you hide it, the actual 'casting' is an obvious act and what it is can be identified with spellcraft.
I would caution against the whole PCs concealing fundamental things from other PCs though. There is sort of a social contract that the party is going to accept any PC a player brings to the table (within reason anyway) and a corresponding reverse obligation to bring something to the table that will be an effective and desirable member of the team. You don't try to fool the party, and the party doesn't conduct an in depth interview and background check to determine your suitability. In particular if it is a player concealing things from other players you are entering PvP territory and you should make sure that everyone agrees on rules for this sort of thing and is happy with them. If the players are all cool with the idea, and it is just their characters that don't know, that is far less problematic.