2 Samuel 24:24
"No," replied the king, "I insist on paying a price, for I will not offer to the LORD my God burnt offerings that cost me nothing." So David bought the threshing floor and the oxen for fifty shekels of silver.

1 Chronicles 21:24
"No," replied King David, "I insist on paying the full price, for I will not take for the LORD what belongs to you or offer burnt offerings that cost me nothing."