Free Credit Card Trial

In MileyWorld if I have a 30-day card day free trial, why I have yet to put the information on my credit card?
I have one day free trial-30 for MileyWorld but I can not understand why they are trying to collect and the need for my address and credit card number. Thanks, MileyCyrusFriend
thats how all the free trials of work – you enter your credit card details and then as soon as it reaches the end of period trial, your credit card is charged – it's all marketing. There is no such thing as a free lunch. They take advantage of people who "forget" to cancel your "membership" at the end of free period and that is how they make their money!
ACAI BERRY ONLINE SCAM!!! Don’t be fooled by the “free trial offer” – it’s NOT FREE at all!