When it comes to playing music (without having to organize it, label it and so on) I usually use apps that are the lightest possible.
I usually do it using the terminal with CVLC, but when I want something graphic, I install LXMusic. LXMusic is the default player of LXDE, and it is very light And why not? Beautiful. Of course, we cannot expect to find anything advanced, as its function is simply: Play music.
Installation in Debian it is very simple as usual. We open a terminal and put:
$ sudo aptitude install lxmusic