How does webcams work? are they really free?

the other day i came across a website about this chick, looks pretty hot. check her out mehorni(dot)com. Her name is Angela (So she said). Now when I went there, it is directed to another website where she claims she does "shows", I emailed her and she claims that it is free to join. Now I am wondering have anyone tried this? I went to the other website and when i tried to register it needed my credit card to verify my age.... wtf?? Will I ever get billed for no reason?