A person who signs up for a credit card that has a special introductory offer, such as low or zero interest for a certain period, uses the card for the duration of the offer, then cancels the card and switches to another with a similar offer, and so on
() rate, as in "rate of interest", and tart, UK slang for prostitute, referring to the promiscuity (in the sense of indiscriminate choice) of such a person