EDIT:
Reader Gena has informed me that it does work on the GBA and GBA SP. The box says that it isn't supported and as I have neither a GBA or GBA SP to test it I assumed the box wasn't wrong. Thanks Gena.

The Nintendo MP3 player is an odd peripheral. On one hand it’s kind of cool to turn your Nintendo DS into an MP3 player but on the other hand, why not get an iPod Nano or something similar. Although, if you’re a Nintendo diehard or maybe just take your DS with you everywhere it might be easier to get this instead. And that’s just how it is with this little device; a series of give and take and contradictions that might make it worthwhile to some.


What's in the box.
Unfortunately the Nintendo MP3 player only comes with the cartridge and nothing else. No headphones and no SD memory card to hold songs. So if you buy this puppy for $50 and then add on headphones for say another $10, and then a 1GB SD card for yet another $50 it takes at least $110 to turn your DS into a functioning MP3 player. Once you’ve acquired all this all you have to do is somehow plug the SD card into your computer and put all your songs on it. You can put them into folders to group them better but thanks to Nintendo rushing this thing you can’t make playlists.


Mario player.
So once you have all those songs in folders on your SD card you just pop it into the Nintendo MP3 Player cartridge and then insert the cartridge into the bottom of the DS. Now here’s another crazy fact, the MP3 player is supported by the DS, the DS Lite, and the GB Micro. It is not supported by the GBA or the GBA SP. What the hell? Also, when you plug it into any of these machines it will protrude from your game player about an inch. What the hell?