This is by far the most common use of the word, and nearly all of it sits in one chapter of Leviticus. When an Israelite made a vow that pledged a person to the LORD, the person was not offered directly; instead a fixed sum was paid to redeem the vow, and the word names that fixed sum. The amount was set by a published scale keyed to age and sex, not haggled over, and a poor person could have it lowered to what they could afford.
Because the amount was a set figure rather than a market price, the word carries the idea of a value assigned by rule. It is used the same way for redeeming a firstborn and for a tax reckoned on each person, and it stretches naturally to the worth of a thing and even to a person reckoned as one's equal, a match of the same standing.
One small feature often surprises readers: the word usually appears with an ending that looks like the possessive your, yet it does not mean anyone's personal valuation. It had become close to a fixed technical term for the set assessment, so English Bibles rightly render it simply the valuation.
Nuances
2aa fixed, assessed sum of money set on a person or property (the redemption price for a vow, a firstborn, or dedicated land; a tax reckoned per head)
Lev 5:15Lev 5:18Lev 6:6(5:25)Lev 27:2Lev 27:3 (2×)Lev 27:4Lev 27:5Lev 27:6 (2×)Lev 27:7Lev 27:8Lev 27:12Lev 27:13
2bworth or price, the value of a thing
Job 28:13
2cone's equal, a person reckoned of like worth or standing
Psa 55:13(14)