The software is free and totally functional without cost to run. Purchasing support hours can assist with setup and troubleshooting. These hours can also be used for custom development. The staff are incredible with support and development. There is a huge list of already supported data sources but they will develop the ability for more if needed.

We used security onion to setup a demo lab where we could monitor our ICS environment. We like the fact that the tool is open source but it requires significant customization and support