(MONEY Magazine) – Amid the public protest over high interest rates on bank credit cards, consumers are learning that low-rate cards aren't always best. The key is how you use your card. The Consumer Credit Card Rating Service of Santa Monica, which recently surveyed more than 400 cards at 230 institutions to find the best, classifies users this way: about one-third are revolvers, who make minimal payments of as low as 2.5% of their monthly balance; another one-third are average users, who alternate between paying in full one month and paying the minimum the next; and the last third are convenience users, who always pay in full. If you are a revolver, you want a low-interest issuer, such as People's Bank in Bridgeport, Conn. Assuming you charge a typical $100 a month, the annual fee and finance charges will total $79.52 a year vs.,say, $131.49 at First Interstate Bankcard, California. As an average user, you want a low annual fee -- or no fee -- and a long grace period before interest accrues, such as the deal offered by USAA Federal Savings Bank in San Antonio, Texas. If you spend $250 a month, your annual cost will be $25.81 vs. $54.88 at Wells Fargo Bank in San Francisco. Convenience users also benefit from a free card and liberal grace periods, such as those offered at Imperial Savings of San Diego.

CHART: NOT AVAILABLE CREDIT: ILLUSTRATIONS BY GROSSMAN BROS. PRODUCTIONS CAPTION: NO CAPTION DESCRIPTION: Issuer, interest rate, annual fee, type of card and grace period for best revolver cards, higher balances; best revolver cards, lower balances; best average-user cards; best convenience-user cards. Illustration: Credit card.