Yes, Zilla is free to start and you can upload photos & videos to Flickr account.
After the free plan quota expires, you can upgrade to a paid plan of your choice at anytime for unlimited uploads.
The free plan comes with an upload of 500 photos/videos.
We make every effort to respond as quickly as possible, and most queries are answered within 24 hours. For any question or help on Zilla Flickr Uploader, you can email us at firstname.lastname@example.org.