I'll be interested to see if anyone has any suggestions I don't know of, but I suspect you'll have a hard time if what you're looking for is a professionally produced podcast aimed at a commercial audience rather than the student audience. Because universities don't product podcasts like that, and there's no money in it (see: your desire to get these things for free - you are not unique in that) so no or few commercial companies try to make a commercial product not aimed at students in a particular classroom or made WITH or FROM students in a particular classroom.

I'm assuming you've tried the resources you get from googling "open university podcast"? Did Stanford have nothing to suit you? I'm seeing a number of pages there that haven't been updated in a while, telling me the heyday of making lots of free podcasts is kind of over.
http://podcast.open.ac.uk/ ?

A lot of resources are now going to involve video, even if just as slides, so if you don't want that either they may not be making things to suit you. :-(