Item sold with an envelope (4)

I believe the answer is:

card

(Other definitions for card that I've seen before include "Thick paper" , "Eccentric - stiff paper" , "A eccentric - a joker, perhaps" , "What may be used for greeting" , "Eg, a heart or club" .)

I've seen this clue in the LA Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.