Some online videoconferencing services also offer free phone conference calling. You use your phone or computer microphone to join the call, and use much less data compared to a videoconference. Vendors such as BlueJeans also allow dial-in users to join a videoconference with phone audio only.

• Blue Jeans and Zoom are avenues you can use to host a telephone conference call.
• Another free service is FreeConference.com, where up to 1,000 people can join by phone. 
• Skype, What's App, and some cellular carriers allow multiple users to connect on a call.