How to calculate the cost of Wowza?

Which plan to choose a large number of users?
There is a service which allows you to conduct daily activities for an hour twice a day. Anyone can hire the service and conduct their broadcast. In total at the start it is necessary to provide simultaneous viewing of about 5000 people online. Broadcasting and 30-40 speakers that transmit video. The whole thing is stored in the video archive on the server. What rate to choose and what is best for our purposes?