'Buy' in the Bible

And Araunah said, Wherefore is my lord the king come to his servant? And David said, To buy the threshingfloor of thee, to build an altar unto the LORD, that the plague may be stayed from the people.

And the king said unto Araunah, Nay; but I will surely buy it of thee at a price: neither will I offer burnt offerings unto the LORD my God of that which doth cost me nothing. So David bought the threshingfloor and the oxen for fifty shekels of silver.