Infinite.

A black card refers to a card that very few people get from banks, which allows unlimited overdraft for purchases. It should be determined based on the fund balance in the shopping card. Each purchase is based on the goods purchased. The accumulated cost of purchasing the goods will be deducted from the shopping card until the funds in the shopping card are used up. Therefore, the use is determined based on the funds. The number of times is not determined by the number of uses.