If your business is in startup and economically you want to use some FREE conferencing tools, Google Hangout is for you. Have you ever checked its service? Its very lightweight and easy to start video conferencing. It has a very nice feature "On Air" that makes it slightly different from others free conferencing tools. Once you see its power, I can bet you would not stop yourself to start using for friends group call or for your official meetings.
Some noted features are -
1. "On Air" feature
2. Integrated with other Google APIs/services. For example, you can schedule meeting at Google Calender for Google Hangout! You can use Google Drive too!
3. Support many to many meeting [More]