Leave it to Wal-Mart to undercut the rest of the market, even in the sub-dollar arena of MP3 music downloads. While numerous blog posts have indicated breathlessly that the price cut is across the board, that's decidedly not the case. There is, of course, a catch: Walmart.com's MP3 store is offering only its top 30 selling tracks for 74 cents each. The bulk of its inventory remains at 94 cents each.

Still, even though it applies to only a handful of songs, 74 cents marks a new low in online music pricing, with Lala at 79 to 89 cents per track, Amazon at 89 cents, and iTunes at 99 cents. The Wal-Mart store now also supports Linux and Mac OS as well as browsers other than IE, including Firefox and Safari.

I love cheap stuff, but I'm lukewarm on the 30-song deal, as the odds that a song I'm looking for at any given moment is in the top 30 are slim. But for hit-driven buyers looking for "Disturbia," "Shake It," or "I Kissed a Girl" this could be a nice way to save a few cents with each buy (or a whole quarter if you've been foolishly purchasing tracks through iTunes), and that could add up to a few bucks over the course of a year.

The good news is that it's easy to see the top 30: They're listed right on the Wal-Mart music store's home page (linked above), so you can do a quick scan of the listings and grab what you want on the cheap, then wander back to Lala to buy your archive tracks.