Two Consecutive text messages and cam rooms?

Are these a SCAM?! I was on a site where u can talk to people and be friends and stuff but certain girls send me a message asking if I want to come to their cam room and I need a card and saying "It's free" <--- is that a lie? 2nd The 2 Consecutive text messaging from another chick asked to do this and (I think u get charged for this) I guess u pay $0.99 for every receiving message. But if u have unlimited everything, how much are u charged?! I really don't trust this at all. Plz help me out.