After reading a dozen or so suggestions on this forum, I found something that allows MP3 PodCast Files (like Car Talk, and other NPR downloaded MP3 files) to play.
Plug your MP3 player into your computer’s USB port, open the Internal Memory folder, go to the Music folder, and create a new folder called PodCasts. Do this even though there is already a PodCasts folder at a higher level.
Drag and drop your MP3 podcast files into this new folder. Close the file browser and disconnect from the computer.
Turn on the SanDisk and select the Home button.
When you see ( Music ) sandwiched between earphone icons. Select the Right Arrow button, and you will see: PlayAll,
keep selecting the Down arrow button and scroll through:
My Top Rated
There’s your new folder PodCasts. Select the Right arrow, and you will see your NPR (or other MP3 podcasts) that you copied to this new folder.