Open Question: How many songs can you down load to a 1.8 GB Mp3?

See people said i could download close to 450 songs. And i can only download 30 songs without me using all the memory space. Am i doing something wrong or something. i put my cd's and ripped them on windows media player and then i sync them. How can i get more song do i have to a play list will that help me get more song and if so how do you put songs on the playlist and how do u put the playlist on your mp3 player?