As of January 2016, the Firestone Complete Auto Care credit card from Credit First National Association offers no interest if the cardholder pays the full balance within six months, explains Credit First National Association. To qualify for this offer, the purchase must be at least $299, and the cardholder must make minimum monthly payments. The cardholder is responsible for paying interest if he does not pay his full balance within six months.
The six-month interest-deferment period begins on the day the cardholder makes a qualifying purchase or on the first day of the billing cycle during which a qualifying transaction posts to his account, whichever date is later, reports Credit First National Association. If the cardholder misses a minimum payment, the bank may terminate the delay period earlier, in which case it provides a written notice to the cardholder. At the end of the delay period, the unpaid balance is added to the revolving balance in the next billing cycle after the delay period.
To determine a cardholder's daily balance of six-month delay purchases, Credit First National Association takes the beginning balance of these purchases each day and then subtracts any payments the cardholder has made towards these purchases, according to the bank's website. After calculating the daily balance, Credit First National Association adds up all the daily balances for these purchases and divides them by the amount of days in the billing cycle to calculate a cardholder's average daily balance.