Charles Ellicott Commentary 1 Chronicles 21:24

"And king David said to Ornan, Nay; but I will verily buy it for the full price: for I will not take that which is thine for Jehovah, nor offer a burnt-offering without cost." — 1 Chronicles 21:24 (ASV)

For the full price. —Samuel simply, At a price (different word). The next clause does not appear in Samuel, but may well be original.

Nor offer burnt offerings without cost. —So Samuel: Nor will I offer to the Lord my God burnt offerings without cost. It was of the essence of sacrifice to surrender something valued in order to win from God a greater good (Ewald).