Amazon users can now trade in unwanted CDs through the Amazon Trade-In Program. The service allows CDs to be sent to a third-party merchant in exchange for gift cards, though at varying costs.

CDs were added to the Trade-In Program on Wednesday. Amazon users can already trade in video games, books, DVDs and electronic items.

The service works by shoppers getting a free shipping label and receiving credit depending on the quality of the discs. Names of the discs are entered and users check off whether the CD is in "like new" or "good" condition, which determines a price. Amazon handles the shipping costs, aside from packaging (which users pay for). Shoppers receive the gift card after Amazon checks the condition of the traded in CDs. The value reflects into the shopper's Amazon account.

It's unknown how much credit users get, as Amazon hasn't updated the FAQ page to reflect CD trade-ins as of writing, though retail experts said $2-3 per CD is likely. Foster the People's "Torches" album, for example, trades in for $2.65.

"There's ... not that big of a market for used CDs," Randy Allen said, an associate dean at Cornell University's Johnson Graduate School of Management. Allen said the hope for Amazon lies in that trade-ins bring more purchases; Research has shown that customers spend 40 percent more than usual from the credit or gift cards they receive from trade-ins.

Not all CDs will be eligible, though. Sellers are required to include the case's artwork, while scratched discs could be rejected (probably depending on the severity).

Experts also said that Amazon will be seen as the go-to place for CD trade-ins as the market continues to shrink, with lower prices and a greater selection of used CDs.

Some experts have advised shoppers to compare CD trade-in prices on websites such as Buyback Media and SecondSpin. Other options are eBay and Craigslist, though eBay requires listing fees and both services require time. There's also no guarantee of a sale, so repeat listings could become expensive. Amazon has the advantage of its service being free and almost instantaneous.

(reported by Jonathan Charles, edited by Surojit Chatterjee)