Cheiromancer
Adventurer
I remember that when discussions of a use activated weapon of true strike comes up, it is generally acknowledged that the true strike feature can't be priced as a first level spell; instead, you treat it as a +20 weapon (very, very epic, even if there is no bonus to damage). I think you have to do something similar with the ring.
I suggest using mind blank as the base spell, and see what that does to the cost. Mind blank gives immunity to most enchantments and divinations, which is roughly as broad as the protection the ring will give to compulsions and summonings. Maybe not worth quite as much; a small discount may be appropriate.
In other words, consider it a variant of a ring of mindblanking which also acts like a cloak of protection/ring of protection against evil creatures. You need to be able to cast mind blank, so you'd need a 15th level caster to make it.
It's cost would be caster level 15 x spell level 8 x 2000 x 0.5 (since mindblank has a 24 hour duration) = 60 000 gp. Discount it down by 25% or so (because blocking summonings is not as powerful as blocking all divinations), to get 45 000.
Joker's calculations indicate that the defensive bonuses are worth about 10 000 gp. I would say that this power should be multiplied by 1.5, since this is a different ability that can work simulataneously with the other powers. So about 15 000.
That gives a final total of 60 000 gp. More than a pair of Friend Shield rings or a ring of spell storing (both 50 000), but less than a ring of telekinesis (75 000) and substantially less than a ring of regeneration (90 000).
Does that seem about right?
I suggest using mind blank as the base spell, and see what that does to the cost. Mind blank gives immunity to most enchantments and divinations, which is roughly as broad as the protection the ring will give to compulsions and summonings. Maybe not worth quite as much; a small discount may be appropriate.
In other words, consider it a variant of a ring of mindblanking which also acts like a cloak of protection/ring of protection against evil creatures. You need to be able to cast mind blank, so you'd need a 15th level caster to make it.
It's cost would be caster level 15 x spell level 8 x 2000 x 0.5 (since mindblank has a 24 hour duration) = 60 000 gp. Discount it down by 25% or so (because blocking summonings is not as powerful as blocking all divinations), to get 45 000.
Joker's calculations indicate that the defensive bonuses are worth about 10 000 gp. I would say that this power should be multiplied by 1.5, since this is a different ability that can work simulataneously with the other powers. So about 15 000.
That gives a final total of 60 000 gp. More than a pair of Friend Shield rings or a ring of spell storing (both 50 000), but less than a ring of telekinesis (75 000) and substantially less than a ring of regeneration (90 000).
Does that seem about right?