Complementing and Complimentary

adjective

• Conveying or resembling a compliment.
  • usage: "a complimentary remark"
• Costing nothing.
  • usage: "complimentary tickets"; "free admission"
  • synonyms: costless, free, gratis, gratuitous

(a.) Expressive of regard or praise; of the nature of or containing, a compliment; as, a complimentary remark; a complimentary ticket.