NEW YORK (CNN/Money) - Best Buy is walking a thin line with its latest in-store test -- one that might thrill cost-conscious consumers, but earn the ire of video game publishers and developers.

The retailer confirmed it has quietly started testing the sale of used video games in select markets, but declined to give details. An analyst note said four stores in Illinois and California are currently involved in the test.

Best Buy doesn't appear to be wading into this half-hearted, though. One of the test stores has over 5,000 used games available, according to Piper Jaffray's Anthony Gikas. Credits earned from traded-in games can be used for other Best Buy merchandise, he wrote.

Previously, big box retailers have avoided selling used games, leaving that market (estimated to be worth $800 million) to specialty stores like Gamestop and Electronics Boutique. Gikas, though, thinks the tide may be turning.