Vagaters will always stay free without any login requirements. The chat rooms are moderated: be a jerk and get banned.
1. Pick a chat room. The numbers behind the room names is the amount of people in that room.
You must "publish" your webcam, before others can request to view it.
To view a video stream, pick a name from the list and click the button under the desired video window.
To send a private message, select a name and click the bottom left button with the room name on it.
You can modify several chat options with the little icon buttons to the left. Check the tooltips.