Credit Card Balance Transfer

I was told that i can enjoy 0% interest free for Credit Card Balance Transfer, but, being a good credit card consumer, i have always made in full payment. However, i think i better tell my friend about this good news as she needs this 0% interest free for balance transferring more than me. Sometimes i was quite saluted those people who have few credit cards in wallet, is it really necessary to hold so many cards? Although credit card does bring benefit as we don't need to keep a big sum of money into wallet, like my hubby said, credit cards only luring people to spend more than what they have earned. I totally agreed this, so, please make sure you won't be sued bankruptcy before you applying credit cards from banks.