Is the BucketVizier application free?

The alpha and beta releases will be free, but the final version will be a paid application. The expected price will be around USD 15 to 20 dollars per license.

Why isn’t the application open sourced?

A couple of reasons, firstly due to lack of resources and time, and secondly, because I need to figure out a freemium model. So this option is a possibility in the future.