complimentary

In the nature of a compliment.

a complimentary remark

But yesterday evening late, when Lewis arrived from down town he found his supper spread, and some presents of books there, with very complimentary writings on the fly-leaves, and certain very complimentary letters, and more or less greenbacks of dignified denomination pinned to those letters and fly-leaves...

Free; provided at no charge.

complimentary drinks

In the evenings, Ward and PJ offer guests a complimentary drink. This gesture seems to reinforce the hosts' desire to make everyone feel welcome.

With respect to the closing of a letter, formal and professional.

The complimentary closing is the word grouping used to bring the message or text to a close.