They figure that if discarding an annual fee attracts customers who spend twice that amount in interest on unpaid balances, they win in the end. Of course, the no-interest trick is impossible if the card comes without a grace period. The grace period is the number of days you can borrow with your card without incurring an interest charge. Though the fine print on a credit card agreement defines this period in very specific terms, most folks consider the grace period as starting on the on the first day of a billing period and ending on the day the bill is due. If the charge was made on the last day of the billing period, you d have just 15 days to frolic interest-free.
Some issuers have shorter grace periods.
You re charged interest the moment a charge is made. Unless digging yourself into debt is your goal, you want nothing to do with any such card. Pick a card that offers a long grace period. There are plenty of other factors that affect the cost of using a credit card. But if you re committed to using your card wisely, they won t apply to you.