Do you not have a laptop or home computer? That's really all you'd need that isn't free.
Like I said, I used my onboard mic and Julian uses Audacity to edit. If "edit" makes you think of some complicated rig you have to navigate, it's really not that complex, especially for audio-only shows, and you could start out just hitting record and talking.
Hell, technically all you really need is a recorder and somewhere to save the files.