Have a gift card you're itching to sell or trade?

There's a site for that. However, it pays to do a little homework before you pack up your gift cards and send them on their merry way.

These days, "consumers are doing everything they can to find the best deals," says Rebekka Rea, executive director of the Retail Gift Card Association, an industry group representing merchants that offer retail-branded gift cards.

Gift card exchange sites, which allow consumers to buy, trade or sell gift cards with the company that runs the site, are a great resource, she says.

Want to get the best bargain for your gift cards? Here are five tips to help.