Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period. Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period. Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period. Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period. Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period. Paying the bills on time is the most important trick of a credit card. In fact, every credit card possesses an interest-free period.