Consider this as an example only, each camera has a different configuration and the results can vary according to the nature of the video the camera is capturing.
Having said that, you can control the bitrate by configuring the streaming settings directly in your camera. Please refer here for recommended settings:
We consider a 512 kbps upload speed to be a minimum for streaming/recording in a reasonable image quality while the average bitrate of cameras connected to Angelcam is around 1200 kbps. The maximum bitrate isn't limited on our end.
With the minimum recommended settings, you will end up transmitting 171 GB per month.
With the average settings, you will end up transmitting 401 GB per month.
These numbers are for one camera which is broadcasting or recording 24/7. Some cameras are able to work with lower bitrates as well and you can stop the recording when you don't need it.