RandomFill is a free Windows utility to randomize the collection of mp3s that will be sent to your portable mp3 player or software media player. It's most powerful feature is the abiltity to assign weights to folders. In other words, folders can be set to be often selected from, rarely selected from, or never selected from.

RandomFill looks for mp3s in recursively scanned folders and/or m3u playlists, and either copies them for downloading into your portable player, or creates a playlist for your software player. The number of mp3s selected can be set to either a maximum size of them, or a maximum playing time.