Amazon.com just launched a new service that lets people swap used video games for Amazon gift-card credit. It's a savvy move by Amazon given the state of the economy and the fact that many video gamers are looking for cheaper options than buying new releases. It's also the latest sign that Amazon is looking to grab more of the video game market, which has shown signs of bucking the recession. Last month the online retailer launched a new store offering downloadable online casual games.

Amazon's new video games trade-in program is widely seen as a direct threat to retailer GameStop, which has dominated the used video game business. Some quick calculations already show that Amazon is offering up to 10 percent more for used games than GameStop. Shares in publicly traded GameStop are getting clobbered, down 13 percent in afternoon trading. Toys "R" Us is getting into the used game business as well and recently launched a pilot trade-in program in a small number of U.S. stores.

Amazon's program lets people search for title and game platform to get the trade-in value, ranging from $10 to $250. Users can print out a free shipping label and receive Amazon.com credit in their account. People who do a trade in before March 19 get a 10 percent off game purchases at Amazon. The incentive is a sign of how Amazon can leverage its giant ecommerce business to quickly stake out territory in a new market.

Many believe video games are strongly positioned in the bad economy as people continue to seek out escapist forms of entertainment, though not everyone is convinced the sector is recession-proof.