In that time frame... I was using sub-GB MP3 players, with MMC cards or maybe SD cards by that point. (I didn't have those massive multi-thousand song collections, so it was fine...)
Because I have pics saved in my personal folder, mine in high school/early college were:
- Classic 64MB w/ 128 MB memory card
- MPIO FL100, probably 2 or 3x bigger; I wore this on a belt holder
- Sandisk Sansa, the bulbous one, before later using some of the smaller ones. Probably still only 256 or 512 MB of built-in storage.