The S1MP3 is a Chinese MP3 player branded by at least 50 different manufacturers. Some only play music, but others can play MP4. Have a look at the gallery to get an idea of the variety. S1MP3.org has been developed to support users of the players and create opensource firmware. Here’s their guide for upgrading the memory of a player. If you can’t get a donor player, the site says you can get a new 1GB memory chip for $9.