Hey, let's have a look at talismans, a specific subtype of magic item in Pathfinder.
"These amulets are imbued with magic that allows them to protect their wearer against a very specific danger. A talisman triggers automatically as soon as the listed condition is fulfilled. Although talismans occupy the neck slot, up to three talismans can be worn on one cord or chain. Wearing multiple talismans in this way offers a greater variety of protection, but a wearer can benefit from only one talisman’s effect at a time. If another talisman would be triggered while its wearer is under the effect of another talisman, that talisman is not triggered and can still be used later." -- Source
Talismans come in greater and lesser varieties. A greater talisman is usable once per day. A lesser talisman is a single-use item that turns to dust after use - Pathfinder loves these kinds of items, though in my experience players hate them. Then again, my players tend to think of treasures in terms of things they invest money in, rather than the older approach of stuff you find randomly lying around. I should do more of that.
Pricing of talismans is odd. A talisman is "use-activated" (it triggers when you do the thing or the thing happens to you - no magic words required), and most of them replicate a spell effect. According to the magic item creation rules (which are guidelines, sure, but this is a relatively simple case): Single use, use-activated item costs (spell level x caster level x 50 gp). This covers potions and so on.
A lesser talisman of beneficial winds, for example, replicates the 1st-level spell feather fall. This requires a caster level of 1, so our calculation is 1 x 1 x 50gp. That is indeed the price of the item! Good.
A lesser talisman of danger sense, on the other hand, replicates the 1st-level spell anticipate peril at caster level 5 (which gives a +5 bonus on a single initiative roll). This calculation is thereafore 1 x 5 x 50gp, or 250gp. However, the actual cost is 750gp.
A lesser talisman of freedom gives 3 rounds of freedom of movement (a 4th-level spell) when grappled, paralyzed, or entangled. It has caster level 7, so our calculation is 1,400gp. However, its duration is drastically curtailed, to 3 rounds rather than the 70 minutes the caster level suggests. Nevertheless, it costs 900gp, which is a very modest discount. Alternatively, the party wizard could purchase a wand with a single charge for 420gp, and cast it before entering the danger zone - this is a bit of a gamble, but it's significantly cheaper, doesn't occupy an item slot, and will last for several encounters. After all, one encounter normally lasts less than a minute!
A lesser talisman of life's breath brings a wearer back to life (maybe) the first time they die. This is a 5th-level spell effect, with CL 9th, giving 2,250gp as our basic cost. The talisman costs significantly more, a mighty 3,500gp.
For single-use items, these are extremely expensive and it's not surprising players disdain them at the levels they're normally available. What's going on? The greater versions costs ten times the price, but are usable once per day.
Part of the puzzle seems to be that quirk in the slot usage. "Although talismans occupy the neck slot, up to three talismans can be worn on one cord or chain." That might explain why a talisman of danger sense is triple the expected price, along with similar items like the sealed summons talisman; the others are harder to calculate.
If that's the case, it creates a weird situation. A talisman is worth more because it has the potential to share a neck slot with up to two other items which are also talismans. That isn't worthless, but it's quite a specific requirement. In effect, talismans push you towards getting other talismans in order to justify the inflated price tag - even though this means you end up paying well over the odds for all three items. Moreover, the range of talismans is quite limited. If you wanted to use a neck slot for anything that isn't a single-use or once-per-day effect, or any effect that isn't covered by the existing range of talimans, you're out of luck.
At the lower end of the scale, there's a perverse effect where somebody who could never afford several talismans probably can't afford one, because the pricing is inflated on the assumption of taking all three. Why the talisman of beneficial winds gets a free ride here I don't know. A 3rd-level NPC sailor could afford a 500gp greater ToBW to survive falling from the crow's nest, assuming they don't need anything else (though the sensible thing would be to have a couple for the ship, which are issued to whoever's climbing the rigging). Our 3rd-level NPC guard can only afford a lesser akoben talisman to resist sleep spells, since the greater version is 4,500gp and she'd need to be 7th level for that, at which point there are many other things she should be investing in, like decent armour.
But wait! Pathfinder has actual rules for incorporating multiple magic item properties in a single slot.
"Multiple Different Abilities: Abilities such as an attack roll bonus or saving throw bonus and a spell-like function are not similar, and their values are simply added together to determine the cost. For items that take up a space on a character’s body, each additional power not only has no discount but instead has a 50% increase in price." -- Source
If we follow that principle, a lesser talisman should cost at most (spell level x caster level x 75gp), and 10x that for the greater versions. Not all of them are straight-up spell effects; however, where they vary from spells, they tend to offer worse benefits, impose penalties, or only trigger after some unpleasant experience (such as being shot at least twice in a single round). On the whole, this is equivalent. There's also the factor that many of them reflexively trigger, whereas in most cases (unlike the talisman of beneficial winds) the comparable spell isn't reflexive. That's certainly worth more! Regrettably, Pathfinder doesn't suggest how much more. As a starting-point, I'll say it's double the cost. If the trigger doesn't help with the effect that triggered it - say, fire resistance only after you've taken fire damage - it doesn't increase.
This would suggest pricing as follows:
75 gp (Beneficial Winds), 150 gp (Akoben), 150 gp (Sealed Summons), 150 gp (Warrior's Courage), 450 gp (Arrow Protection), 150 gp (Pentacle), 450 gp (Scarab), 450 gp (Triskelion), 300 gp (Danger Sense), 900 gp (Freedom), 1,250 gp (Ankh), 750 gp (Protection from Flames), 150 gp (Good Fortune), 2,100 gp (Healing Power), 3,000 gp (Hamsa), 3,500 gp (Life's Breath)
The scarab talisman is tricky. Immunity to a very limited subset of poisons and to distraction, for the duration of one combat, only if the rerolled saving throw is successful? The 3,000gp swarmbane clasp gives immunity to distraction and allows the wearer to deal full damage to swarms, permanently, but doesn't help with poison. Assuming the poison immunity and damage benefits are roughly equivalent, that suggests the talisman should be closer to 300 go, boosted to 450gp because it's a shareable slot.
As for the talisman of danger sense? Games really really want initiative to be valuable, but in reality, it's only valuable in the first round of combat and only if it allows you to go before the enemy. After that, everyone's going cyclically. Still, that's not my call. On the other hand, heightened awareness is also a 1st-level spell, which hangs around much longer than anticipate peril, and gives you a flat +4 bonus to initiative without the need for any heightened caster levels. That suggests the real value of the talisman is much lower, around 300 gp since it's reflexive, and it gives a +4 bonus.
The talisman of good fortune allows rerolling a die, and only a natural 1. This is a strictly worse, reflexive version of hermean potential and worth far less than suggested here.
The talisman of healing power is almost twice the price of an equivalent potion (by pricing rules, 1,400 gp). It's functionally similar to greater false life, which would cost 2,100 gp and gives temporary hit points, with the same net result. Given the long duration of a 7th-level greater false life, paying for the reflexivity seems excessive. The aegis of recovery gives slightly fewer hit points, but triggers under much nastier circumstances (imminent death, not moderate injury) and gives an ongoing bonus to a variety of saves, for only 1,500gp.
The talisman of freedom is too hard to judge. Translating down freedom of movement into a reflexive ability that lasts for three rounds instead of 70 minutes is simply guessing. Given how nasty being grappled, paralyzed, or entangled can be, I've left it untouched. Same goes for the hamsa and ankh, whose effects are weird enough that determining what's being charged for is beyond me. The talisman of life's breath is actually a reasonable price.
Of course, these prices are still only appropriate if you're going to wear three of them in the neck slot. If not, they should be even cheaper!
Fundamentally, the issue comes down to hard-coding a conditional benefit into the price of the items. While I do like the idea of talismans and enjoy using them when I can (at the normal prices, too), by putting this weird exception into the rules, they've ended up with prices that don't really reflect the utility of the items.
