a purchase: what is gained by paying money for it, whether the buying itself, the price handed over, or the property so acquired.
This is the noun "purchase," built from the verb "to buy" (קנה). It labels whatever is bound up in getting something by paying for it: the act of acquiring it, the price handed over, or the property that changes hands as a result. Which of the three is in view depends on the sentence, but the single thread running through all of them is that money changed hands.
Because the word can land on the deal, the payment, or the goods, English versions shift with it: "purchase," "price," "possession," or "bought with money." In the account of Abraham it names the field at Machpelah once it is legally his by buying it (Genesis 23), and in Jeremiah it is the sealed deed that secures Jeremiah's field at Anathoth (Jeremiah 32). In the laws about servants it marks a household member "bought with money," a person acquired rather than born into the family (Genesis 17; Exodus 12).
A natural partner is the word for a "sale" (מִמְכָּר). The two stand side by side in the rule that lets a bought servant be redeemed (Leviticus 25:51): one word for what the buyer gained, the other for what the seller gave up.