Missing Memory with Mac

Using Mac OS with the 4GB model. I have 338 songs at an average of 3MB each so should not have much more than 1 GB of memory used. All podcasts, audiobooks have been deleted. So why do I only have 208MB of memory left? Yes, I could do yet another re-format and reload the music. Oh so tedious. Searched lots of old posts and see nothing regarding this. There is some type of hidden gremlin stuff. I do delete the little 4k things the mac creates regularly.

Any tips from the experts would be appreciated.

Yes, I have emptied trash and cleared all the little stuff Mac leaves. Somehow, I thing all the podcasts, which have since been deleted, leave some old fingerprint, which soaks up memory. When the podcasts are deleted, you never get all the memory restored. I often totally delete the podcast and audiobook options. Not much difference.