Magic item creation, other bonuses

[schreier]

In the creation rules, armor class bonuses other than deflection have a 25% premium. Save bonuses other than resistance have a 100% premium (cost double)

I don't see any discussion on skill bonuses other than competence ... Is there guidance anywhere?

Thanks

[Biggus]

I don't know of any specific guidance, but I think the answer is probably that they cost double what competence bonuses do. My reasoning is:

The cheapest AC bonuses aren't deflection but armor enhancement bonuses, which cost 1000GP x bonus2, whether you're talking about actual armor or bracers of armor. Deflection and natural armor enhancement bonuses have a 100% premium, and others have a 150% premium.

So, as save items have a 100% premium if they're not the cheapest type (resistance), and AC items have at least a 100% premium if they're not the cheapest type (armor) it seems a fairly safe assumption that skill bonuses also have a 100% premium if they're not the cheapest type (competence).

Some types may have a 150% premium depending on the DM's preference.

[Segev]

When getting equipment for improving skill checks, don’t forget that masterwork gear is 50 gp for a +2 circumstance bonus.

[TristanS]

200% seems reasonable without other guidance ... 25% is immaterial. Would you treat stacked bonuses like secondary items you think (50% premium)?

For example:
+10 competence bonus to a skill = 10^2 * 100 = 10,000

add +5 sacred bonus to the same skill (assuming bonus squared x 200) = 5^2 * 200 = 5,000

Would the item be 15,000, or 17,500 you think (17,500 = 10,000 + (5,000 x 1.5))

[Jay R]

I can't answer for the general case. Tell us the specific item you want to design. That will make a huge difference in cost.

Far more importantly, it will determine if the item is feasible at all.

As DM, my answer to the question as asked would be this:
Pay 50 gp for a +2 circumstance bonus -- if there is an item that can plausibly add to competence (skeleton keys for picking locks, special running shoes, etc.).
Use the prices listed for a competence bonus.
Anything else is not allowed without special permission, and a good justification. Then it will be priced individually.

I probably would not allow cheap stacked item. If you want +10 to a skill, buy a +10 item at the listed price; don't try to buy two +5 items just to cut costs.

Having said that, I respect good rationalizations. Here are a few that have occurred to me:
Fins on your feet for an enhancement bonus for Swim
A rod of Asclepius for a divine or insight bonus for Heal
Chocolate as a one-use morale bonus for almost any mental skill.

But the crucial thing is this: anything beyond the rules will require a DM ruling, and will probably need to be a specific item.