Licensing is very simple. There is the product and then Flow and VoIP licenses. If you just want to analyse standard application traffic then there is no more to spend. The Flow and VoIP licenses are inexpensive.

There are certain licensing costs. For example, if you use NetFlow, you need to purchase a license depending on the size of your connector. Similarly, for voice monitoring, you need a separate license. Apart from that, I'm not aware of any additional costs.