Balance transfer cards are credit cards that are intended specifically for balance transfers. They usually offer low or zero rates on balance transfers, as well as low introductory APR to attract new customers. Balance transfer cards can save you money in the short run. But it's important to pay off your balance during the low APR introductory period. After it ends, balance transfer cards revert to a higher standard rate of APR, and your debt will start to increase much more quickly.