'Buy' in the Bible

Then Araunah said, “Why has my lord the king come to his servant?” And David said, “To buy the threshing floor from you, in order to build an altar to the Lord, that the plague may be held back from the people.”

However, the king said to Araunah, “No, but I will surely buy it from you for a price, for I will not offer burnt offerings to the Lord my God which cost me nothing.” So David bought the threshing floor and the oxen for fifty shekels of silver.