Trade unwanted gift cards for cash

(CNN) - Did you end up with a gift card you know you won't use this holiday season?

There's a way to turn those cards into cash.

You can sell those unwanted cards online or with new apps.

Two websites like raise.com and cardpool.com are popular in the US.

But there is a hitch. It's not an even trade.

Most websites take a cut off the face value or charge a hefty transaction fee depending on the amount of your card.