'Buy' in the Bible

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

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