giveaway

Short definition from Wiktionary

Noun

1. 1
   Something that is given away or handed out for free.
2. 2
   An event at which things are given away for free.
3. 3
   The act of giving something away for free.
4. 4
   An indicator that makes something obvious or apparent.

Adjective

1. 1
   free of charge, at no cost.
2. 2
   very low.