I am looking for software that would emulate a jukebox in functionality. I would like to have it 'read' the mp3's on a dedicated hard drive and then list them and allow selection and play with either a number selection or a mouse click.

And of course, since I am still poor, a freeware, shareware or very inexpensive would be a bonus.

Thank you.

It's not quite "jukebox", but I'd say Kodi is your best bet.

Or just about any file manager on any o/s platform?

At its most simplistic, sure. But will a file manager queue up a file in an already opened media player? Or would it start a new media player so you have two competing audio tracks playing simultaneously? Or will it replace the currently playing track in the already open media player? I don't know -- the bash command line is my file manager.

On Windows, WinAmp (at least, the old old version I'm using) will do that. It's a configuration option, I think the option is called "enqueue as default action".

Out of the box a bit, but perhaps try Plex with a cheap Roku stick or something. The remote would be a super easy way to control the Jukebox and would eliminate the need for a separate computer. All you'd need is the display. You would also get the UI with all the pretty cover art and metadata and stuff that you'd want in a Jukebox.