As time runs out for gift buying, many people are turning to gift cards to fill up their holiday lists.
And those cards can mean billions in cash for retailers.
The National Retail Federation estimates that ten percent of the $80 billion in gift card sales will never be spent.
And that leftover $8 billion goes right to the companies' bottom lines.
Rules for gift cards vary: Some cards never expire, while others allow "dormancy fees" to chip away at the card's value.
