No-Cost Bonus Addition to a Subscription Box

This page is the CodyCross answer for the clue below from Underground Worlds, Group 2177, Puzzle 4 (Edinburgh Vaults).

Question is: No-Cost Bonus Addition to a Subscription Box

and the answer is: FREEBIE

Word Meaning:

FREEBIE — (informal) Something which is free; a giveaway or handout.

Definitions from Wiktionary.