Bentonville (AR) - Wal-Mart announced today that it has begun selling unprotected MP3 files at its online music store at prices that still undercut most other DRM-ridden tracks.

Wal-Mart, the country’s largest music retailer, said Universal Music and EMI Music are among the flagship record labels participating in its new music download service.

The DRM-free tracks carry a price of 94 cents each. That’s still five cents less than the standard price for a song with copy protection on Apple’s iTunes or Sony’s Connect, the two top online music sellers. Wal-Mart’s online music store charges 89 cents for music tracks embedded with proprietary DRM (digital rights management).

iTunes began selling a selection of DRM-free music earlier this year at $1.09 per track. Amazon and Emusic are among the other digital download stores that have moved into the unprotected MP3 music market.

Sony Connect is the biggest online store to not move into the emerging music market. Sony’s record label Sony BMG has likewise refused to offer legal versions of its music without some sort of copy protection.

Wal-Mart’s move to include content from Universal comes after the music publisher said it would move into the DRM-free space, but would not give such content to iTunes. Universal is the largest music publisher in the world.

This new trend in music downloading is seemingly spawned from an open letter from Apple CEO Steve Jobs. Earlier this year, Jobs called out music record labels, asking them to offer a more standardized version of their music in a legal online outlet.