Periapt of Resilience (help me price?)

[Astalanya]

Periapt of Resilience:
At first glance, this item merely appears to be a scissor-cut topaz set upon a silver choker. However, when worn, it grants the wearer a +2 resistance bonus to her Fortitude saves.
Faint abjuration; CL 5th; Craft Wondrous Item, resistance, creator’s caster level must be at least three times the periapt’s bonus; Price: ??; Weight 1 lb

Greater Periapt of Resilience:
At first glance, this item merely appears to be a silver choker studded with golden topazes. However, when worn, it grants the wearer a +4 resistance bonus to her Fortitude saves.
Faint abjuration; CL 5th; Craft Wondrous Item, resistance, creator’s caster level must be at least three times the periapt’s bonus; Price: ??; Weight 1 lb

I think this should be fairly straightforward, but I'd like to make sure I've done pricing right.

The average cost for resistance bonuses to all saves:
+1 - 1000 gp, +2 - 4000 gp, +3 - 9000 gp, +4 - 16,000 gp, +5 - 25,000 gp.

My thinking here is this: if the save bonus only goes to one save, not all, shouldn't that qualify for a price reduction? If so, should I factor it as:
1. one-third the cost of a standard resistance bonus? (one save of three)
2. two-thirds the cost of a standard resistance bonus?
3. one-half the cost of a standard resistance bonus?
4. something else?

 

[ARandomGod]

First of all I'd make the item a +2 unnamed bonus to fort saves, and price it at 10K (pricing it as an item that duplicates a feat). The Greater one I'd probably price at 25K... or just not allow.

But since you're calling this a resistance bonus, so that it won't stack with cloaks of resistance...

I'd make it +3 for resist and price it at the same price as an item of +1 to all resists. That's the same total amount of resistance. For the greater I'd have it be +6... But I'd price it at the same price as +3 to all... just because.

For +2 resistance bonus to one save. I think that 1/3 of the price of +2 to all is a fair place to price it. Of course, it looks like a little more that I'd price it at if you look at the above suggestion. Same for +4, I'd just have it at a flat 1/3 of the price of a resist all +4 item.

 

[Cheiromancer]

I could see an argument for making it 1/5 the cost of the equivalent bonus to all saves. i.e. 800 gp for +2. Have one such item taking a slot, the other two items (for the other two saves) slotless (x2 cost) for 1600 gp each. Total; 1 slot and 4000 gp for +2 resistance bonus to all saves, the same as cloak of resistance +2.

Now, the improved flexibility should up the cost a bit. (You can share the items among three characters to cover their poor saves, say). But this would be worth just a bit extra. Maybe 1/4 instead of 1/5. Then a +2 periapt would maybe be worth 1000 gp. Which is not too far away from the 1/3 price of 1333 gp, but that might be too expensive.