Q: What is the least expensive software to record and edit a podcast?

A: The least expensive software is Audacity - and it's FREE.

And being free doesn't mean it's low quality either. Audacity is a professional software available for Window, Macintosh and Linux. It includes all the tools a professional sound engineer needs.

You can download Audacity at http://audacity.sourceforge.net/

You also need to download the LAME encoder to enable Audacity to export in the mp3 fileformat normally used for podcasting.

You can download the LAME framework at http://lame.buanzo.com.ar/