Interest on outstanding balances

Interest charges vary widely from card issuer to card issuer. Often, there are "teaser" rates in effect for initial periods of time (as low as zero percent for, say, six months), whereas regular rates can be as high as 40 percent. In the U.S. there is no federal limit on the interest or late fees credit card issuers can charge; the interest rates are set by the states, with some states, like South Dakota, having no ceiling on interest rates and fees, inviting some banks to establish their credit card operations there. Other states, like Delaware, have very weak usury laws. The teaser rate no longer applies if the customer doesn't pay his bills on time, and is replaced by a penalty interest rate (for example, 24.99%) that applies retroactively. So customers should be wary of these offers, that usually contain some traps