Assuming an average song length of 4 minutes and a bitrate of 128kbps, 50GB of tracks will contain approximately 12,500 songs. 50GB of storage is the amount of storage that comes with the Live365 Broadcast 2 package.
As a rule of thumb, 1Mb is equal to 1 minute of music at 128KBPS. So a 50Gb library is about 50,000 minutes of music. Of course, in some genres, like Punk, the tracks are shorter (as short as 2 to 3 minutes) and other genres like Trance or Freestyle Jazz, the tracks can be considerably longer.
With the Live365 Broadcast 1 package, you get 25GB of storage, which is approximately 6,250 songs. (Assuming 128kbps and average 4 minute length).
With the Live365 Broadcast 3 package, you get 100GB of storage, which is approximately 25,000 songs. (Assuming 128kbps and average 4 minute length).