Pricing a Magic Item

[Torivor]

The guide for pricing magic items at the back of the core rule book is very helpful, but sometimes you have a great idea for a magic item and you the rule book just can't be specific enough. I need some help with caster level, pricing, and construction requirements for this magic item:

Ring of Shadows
Aura Strong Necromancy CL???
Slot Ring Price ???
Description
This silver ring is set with a rare black sapphire that glows faintly in complete darkness. Once per day, by speaking the command word and stretching out his hand, the bearer of this ring can force an incorporeal undead creature (such as a shadow) no more than 60ft away to make a DC 22 Will save or be drawn into the ring and trapped there permanently. Thereafter, the bearer of the ring can speak another command word to release the shadow force it to serve him as per the spell Command Undead but with no saving throw. Intelligent undead may attempt a new saving throw to escape every new moon, but some decide to remain anyway if their master is consistently providing them with victims. If the ring is placed in an area of bright light for the duration of the new moon the undead take a -5 penalty to their will saving throw to escape. The ring can contain up to 20 HD of incorporeal undead at a time, and multiple entities can be contained in and released from the ring at once.
Construction Requirements
Trap the Soul, Command Undead, a black sapphire worth at least ??? gp, ???

[Torivor]

Here's my current thinking:

CL 15 for Trap the Soul

Cost:

8 (spell level) x 15 (CL) x 750 / 5 (one charge per day) = 18,000 gp for Trap the Soul 1/day
50 x 1000 = 50,000 gp for Trap the Soul Material component
2 (spell level) x 15 (CL) x 750 x 75% (similar to a staff) = 16,875 gp for Command Undead (unlimited)

The other limitations/bonuses roughly balance out I think.

= 84,875 or let's just say 85,000 gp for it's cost to create, giving a market price of 170,000 gp

Is that too much or is it reasonable?

[ryric]

You're not really getting the effect of trap the soul, so using it to price the ring doesn't seem like the best way. Let's look at what the ring fundamentally does:

-It instantly defeats an incorporeal undead creature that fails its save.
-It conjures that creature in the future to serve the wielder.

First, you should set a duration for the control effect, and does the trapped undead get a new save when the user attempts to suck it back in?

Given the high limit on undead HD, I'd say the first effect is similar to undeath to death, and the second is analogous to a summon monster IX. I wouldn't worry about the material component. Based on that you'd be looking at ~32,400 gp (command word) for trapping the undead, and 243,000 gp for having an undead servant at your beck and call all day. But, having to actually trap an undead before you can use it is a serious limitation, especially because if the undead is killed you need to find a new one. If you call that effectively 1/day you get 48,600 for the summoning ability. Adding those up I get 81,000, which is pretty close to you estimate.

So after all that I'd say, sure, 80k-85k seems like a good range.

[Dastis]

Are you making this as a player or a dm?

[Pizza Lord]

I would use the mirror of life trapping as a baseline/guideline.

• Mirror is 200,000 gp. and CL 17; uses imprisonment, which is likely just as appropriate as trap the soul, but trap the soul works just fine for the ring.
  
• I'd say the ring is probably CL 15th, and the DC to resist is 22, 8th-level effect + 4 for the needed requisite ability score. Technically you aren't casting that spell but the effect is nearly identical, so you've got that right.
  
• Mirror holds 15 creatures regardless of HD, ring holds 20 HD. Assuming about a minimum of 3 HD for most incorporeal undead, that's about 6 trapped creatures at a time, maybe 7. Obviously the weaker you go, the more creatures you get... but they're weaker. However, unlike getting a swarm of celestial monkeys from undercasting summon monster spells, even weak incorporeal undead should never be underestimated.
  
• Mirror lets you call forth the prisoner for questioning/ Ring lets you call them forth under your command.
  
• Mirror is fragile and can be destroyed easily. Ring not so much, but takes up an item slot.
  

So 200,000 baseline. Divide by a little more than half for only effecting incorporeal undead specifically. Add more for the 20 HD of Command Undead, with no apparent new saves against the command (except maybe suicidal ones) and they don't get a new save when re-trapped. A save every month basically, probably with a huge penalty because 'bright' light is easy, not like it has to be 8 hours of sunlight per day of the new moon. Then a bonus for being a ring slot item.

I'd guess about 125,000 to 150,000 in price, just estimating.

[grudgekeyper]

The ring in the end allows for continuous control undead as they are forced to obey and are no limitations on how long you can use the shadows outside of the ring.

Continuous Control Undead (CL13 * SL7 * 2000) = 182,000
Modifier Incorporeal Undead Only & Chance to escape Lets say 25% = -45,500
So minimum cost would be 136,500.

With the ability to store and release with a command word I would probably increase the cost back to typically Control Undead but that's a judgement call depending on what you base it on. (Extra-dimensional spaces start at rope trick and go up)

[Zarius]

To be honest, THAT seems like an artifact. Based off the book's pricing, you'd be in the right ballpark. But also remember that it'd TECHNICALLY benefit from a 'limited circumstances' reduction (under creating Cursed Items), because it only works on Incorporeal undead. And that's a pretty severe limit, so that could EASILY be justified upto 30%, especially since I can't think of any incorporeal undead off the top of my head that AREN'T intelligent, and thus would get the monthly save to break free.

But incorporeal also tend to be the most powerful, so I'd class that as an artifact, personally.