clearstream
(He, Him)
I considered a method similar to Lords of Madness, which offers that "The basic method for determining the value of a slave is based on the creature’s CR, using the following formula: Cost = (CR, minimum 1)^2 × 100 gp. An unskilled dwarf, for example, with CR 1/2, costs 100 gp (CR 1/2 rounds up to 1; 1 squared = 1; 1 times 100 gp = 100 gp). A troll slave, on the other hand, costs 2,500 gp (CR 5 squared = 25, times 100 gp = 2,500 gp). Unusual or marketable qualities in a slave, such as great strength, great beauty, valuable skill, or exotic origin, can multiply the price by two, three, or four. A skilled miner dwarf might bring 200 gp if sold at a mine. If that same dwarf were exceptionally strong, he could cost 400 gp. If that dwarf was an 8th-level rogue and the buyer was the head of a thieves’ guild, the slave could cost between 12,800 and 25,600 gp." Regarding their examples, I feel they don't give enough thought to the slaves earnings potential for the owner which historically appears to have been a central element of pricing. That skilled miner for instance is going to yield far more than a dwarf that is merely strong.The 3e book Lords of Madness has suggestions on pricing slaves in the section on Neogi, and the 2e historical sourcebook on Celts also has a pricing guide, if you want "official" prices. (Don't have these in front of me at the moment, mea culpa.)
I like that the formula recognises a need to exponentiate for more powerful creatures, although I feel it scales too weakly, e.g. 57,000gp feels low for an Ancient Gold Dragon to me. It's hoard will contain quintuple that in coins alone. It's also broken in that it has to be corrected with a minimum of 1 for CR in order to avoid raising a fraction to a power. Where I landed was to continue with the principle (from another thread) that tier equivalence for non-PCs is based on HD. So a Troll (HD8) counts as tier 2. And anything much more powerful than that will be "priceless" - i.e. not bought and sold as a slave.