Jitsi (Meet) is an open source software and can be used on the PC via a browser, for cell phone and tablet a free software is necessary. The Jitsi Meet servers run the video conferences, the software itself is free. The advantage of having your own server is that they are independent of other users on the server (for example, at peak times) and you can choose the physical location of the server. We do not offer demo servers, but the software itself can be tested on free servers. The official Jitsi site offers the possibility to test the software: https://meet.jit.si/