We plan to use five stream engines.
(one- repeater, three- edge server, one- load balancer)
I have a few questions about billing.
Can I pay monthly or annual license fees Or do I have additional costs per traffic?
Also, is the ADD ON module free?
Hi Neo, for wowza streaming engine, you will be charged by per server license usage, if you run wowza on 4 machine then you need to pay 4*95$ per month or per server you can pay the bill annual.
there is no costs for your traffic on wowza side, because you run wowza on your own server so no one can tell you the limit 
you can serve depending on your server network and cpu capacity ( ie : you can use 10gbit server then you will get 9k concurrent user with 1 mbps stream with single wowza )
I want to note that why dont you think about using wowza cdn ? Because in cdn you pay only the usage , unfortunately in dedicated server, you have to pay the server & wowza price even if you use or not .
How many visitors do you expect ? What’s your peak visitor estimation ? how many hours will you publish the stream ?
Thank you for your kind reply. I’m still planning it, so I can not tell you exactly the visitor figures. In addition, I will also consider the CDN. Thank you.