cost formula for mounts

[Shades of Eternity]

I'm thinking of adding a ton of new potential mounts to d20, but want to create some sort of formula in order to ensure it scales well.

here's what I got?

# of Hit Dice (squared) x 20
Pretrained skill package (trained for combat) +50%
Individual tricks +10% each
Creature can never be used a mount (to small, unusally, or dangerous) -25%

Unusal creature/template x 2 all costs
Flight: x 2 all costs

***********************

will it work, and is their anything I need to take into account?

 

[ValhallaGH]

Start with Warhorse stats. 4 HD, trained for combat, cost: 400 gp.
If trained for combat adds 50% to the cost, that's 1/3 (~133 gp).
So the horse itself costs ~266 gp. For 4 HD of large creature.

Now you have a basis for setting consistent costs.

 

[Shades of Eternity]

let me make sure I got this right

warhorse

base: 400 gp


disection
trained for combat: 200 gp

so 200 gp left

divided by 4: 50 gp

so 50 gp/hit dice untrained
or 75 gp/hit dice trained for war?

I think I'm missing something.

 

[ValhallaGH]

75 x 4 does not equal 400gp.

Being trained for combat is 1/3 of the final cost (no extra tricks, no special movement, etc). Combat training makes total cost 150% of animal cost. So combat is 1/3 of final cost.

1/3 of 400 = 133.3333333...
400 - 133.333333... = 266.6666666...
1/4 x 266.666666... = 66.6666666... per hit die.
~66.67 gp per hit die, base animal.
100 gp per hit die, combat trained animal.

Now, the Light Warhorse is 150 gp. By the same math process you get:
~33.33 gp per hit die, base animal.
50 gp per hit die, combat trained animal.


Going from 3 to 4 hit dice doubled the cost per hit die.

Extrapolating, a 2 HD war mount would cost 25 gp per hit die = 50 gp total. A 1 HD war mount would cost 12.5 gp per hit die = 12.5 gp total. Base die costs are 16.66... and 8.33... respectively.
In the reverse, a 5 HD war mount would cost 200 gp per hit die = 1,000 gp total. A 6 HD war mount would cost 400 gp per hit die = 2,400 gp total. Base die costs are 133.33... and 266.66... respectively.

Turning that into a mathematical formula requires more skull-sweat than my brain wants to do right now. But that should give you a solid starting point.

 

[Ilja]

Going by Valhalla's counting, the formula would be:
HD*6,25*2^HD (and for untrained, it would be 4,17 instead of 6,25).

Light Warhorse: 3*6,25*2^3 = 3*6,25*8 = 3*50 = 150
Heavy Warhorse: 4*6,25*2^4 = 4*6,25*16 = 4 * 100 = 400.

Anyways, I don't think that is completely correct anyway. You can't use it for creatures lower than 3 hd; a warpony is 2 hd and costs 100 gp, not 25.

I think that you should modify for intelligence too. A pegasus is basically a flying heavy horse with intelligence and minor magical abilities (reaaally minor by the time you get it). It costs 4000 gp.
Pegasus (with x2 for flight and x2 for unusual) = 1200 gp with your counting. 1600 if you mean to have x2 + x2 stack into x4 instead of the normal x3.
I don't know where you got x2 for unusual and x2 for flying from, but I would have put at least x4 for flying, x3 for unusual, and x2 for every 4 points of intelligence score. So a pegasus would be 400*(4 for flying, 2 for unusual, 2 for intelligence 8+)=400*8=3200.

 

[ValhallaGH]

Thank you, Stringburka. (Check your final pegasus formula; there's an inconsistency in the "unusual" variable.)

I'd forgotten about the warpony (all the Small characters in my games end up on riding dogs). That's a serious point.


Well, it's apparent that the existing economy doesn't follow a predictable formula. The combat training seems to double the cost, if not more than triple it. Alternatively, it doubles the cost, to a minimum of 100 gp.

I suspect that Pegasus cost is x2 (not Animal type), x3 (Flight speed), x3 (Rare), x2 (Smart) = x10, which converts 400 to 4,000 gp.

Regardless, good luck to the op. I hope some of this stuff has been helpful.

 

[Ilja]

I see no inconsistency though. When multiplying in cases such as these, you lower each factor beyond the first. A factor of x3 should be +200% cost. So base 100% + flying +300% + unusual +200% + Int 4 100% + Int 8 100% = 800% of base cost.

Don't know how you count in the second example, but x2+x3+x3+x2=/=x10 though. What you do is basically add +100% for not being an animal, which I think is a great idea, but it still adds upp to 3600 gp.

 

[ValhallaGH]

I would have put at least x4 for flying, x3 for unusual, [sic] So a pegasus would be 400*(4 for flying, 2 for unusual, 2 for intelligence 8+)=400*8=3200.

1) That is the inconsistency I was referring to. No need to get defensive about it.

2) I used the same computational method you did. (4 + 2 + 2 = 8; 400 x 8 = 3200. 2 + 3 + 3 + 2 = 10; 400 x 10 = 4000.) I just used different numbers for parts of it.

3) I do think that getting a creature type other than animal is a powerful factor, and one that should bear on the cost. I'm glad that you seem to agree with that part.

 

[Ilja]

I'm not going to the defensive, sorry if it sounded that way. English isn't my main language, so sometimes it comes out wrong.

I think we do count differently.
When adding together factors such as x2, x3, and x4, everyone but one should be reduced by 1.
So if we say that flying is x3 (that is, a flying heavy warhorse is 1200 gp), non-animal is x2 (a beast heavy warhorse is 800 gp), rare is x3 (an extremely unusual heavy warhorse is 1200 gp) and intelligent is x2 (a smart warhorse is 800 gp), one that has several of those doesn't have it added up like x3+x2+x2+x3. The increase in cost is what is added, so a flying heavy warhorse costs 800 gp more than a normal one, and a smart warhorse costs 400 more than a normal one. A smart, flying warhorse costs 1200 more, that is it costs 1600 (a factor of x4, not x3+x2).

When you write x2, you include the base price of the mount (400 gp). I'm of the opinion that you only need to pay this once, and that the modifiers are added onto that. Thus, your example of x3, x2, x2, and x3 is added as Price*(3+1+1+2). My example of x4 (flight), x3 (unusual) x2 (int 4) and x2 (int 8) is Price*(4+2+1+1).

This is the same as is done for criticals - imp. crit increases crit range by x2, keen increases by x2, the total is crit range is x3 (15-20 for keen longsword with imp crit).
(Don't remember if keen and imp crit stacks in 3.5 though [blush])

However, you could simply add the multipliers together. It's a little unorthodox, but it could fill the purpose of dramatically increasing price for several lighter abilities.

 

[ValhallaGH]

Well, yes, that's how multiple multipliers (and the English gets confusing no matter what your native language is) are combined in D&D. (And no, keen and imp. crit. do not stack in 3.5; apparently the 3.0 kensai with a keen katana and improved critical for a threat range of 13-20 [or 9-20 if your group applied the +2 threat before multipliers] convinced them that it was a wee bit over-powered. )

I was choosing to simply add the multipliers and go from there. It gives results that map to at least a few points in the SRD options for mounts, and provides a system that allows for pricing home brew mounts on an equivalent scale, which was the point of the original post.