How much does it cost to start a private podcast?

You can use a podcast hosting provider to create episodes and send them to your private podcast subscribers. Transistor is a platform that supports private podcasting, and its plans start at $19/month.

If you already have a PC or tablet, the only equipment you'll need is a USB microphone. The Samson Q2U is a good choice, costing $60-$100. Recording and editing software can be free (GarageBand or Audacity).