How much is a hit die increase worth?

[martixy]

I'm looking for an estimation on the monetary value a hit-die increase(past and future HD) might carry - up to a max of d12. Although - is there a conventional middle-ground between d12 and d20?

[Snowbluff]

1 hp per level. Roughly 8,000 for an alternatively typed +2 bonus to con. Slightly worse than that, of course, since you don't get the bonus to fortitude.

[Mystral]

I'm looking for an estimation on the monetary value a hit-die increase(past and future HD) might carry - up to a max of d12. Although - is there a conventional middle-ground between d12 and d20?

It adds one HP per level, so it would like giving someone +2 Constitution. So, I guess 4000 GP, since it doesn't add to constitution based skills and fortitude saves, but is an alternate way and can be combined.

For scaling beyond 1d12, well, you would want something that produces an average of 7.5. Since the 1d14 is not very common, I suggest you go 2d6. After that, 1d6+1d8, 2d8, then 1d8+1d10 and then 2d10 or 1d20.

You can skip the 2d6 if you're feeling generous, then it's a leap of 1.5 HP/Level instead of 0.5.

[martixy]

Since the intent is have it be a permanent, non-magical ritual-type thingie, it might be worth a bit more.
Which I just realized is basically equal to receiving the Improved Toughness feat, so that's another way to look at it.

P.S. I'm also not fond of either complicating the whole concept with multiple die(it is called a hit die(singular) for a reason after all) or the big jump from d12 to d20. So I'm thinking to just leave it as a max of d12 for now.

[Flickerdart]

Since the intent is have it be a permanent, non-magical ritual-type thingie, it might be worth a bit more.
Which I just realized is basically equal to receiving the Improved Toughness feat, so that's another way to look at it.
IIRC Arms & Equipment Guide suggests that feats might be priced at 10,000gp + 10,000gp per prerequisite. While that is far too cheap for many feats, it seems about right for Improved Toughness.

[MisterKaws]

There is no progression for hit die above d12, although the divine progression might work. The Dragon Ascendant PrC increases the hit dice results to an above average value, giving 1hp per hd, but never more than the maximum value, and culminates at maximizing the HD value of a dragon, just like a god has full HD from all sources.