A firm customarily buys its supplies and materials on credit from other firms, recording the debt as an account payable. This trade credit, as it is commonly called, is the largest single category of short-term credit. Credit terms are usually expressed with a discount for prompt payment. Thus, the seller may state that if payment is made within 10 days of the invoice date, a 2 percent cash discount will be allowed. If the cash discount is not taken, payment is due 30 days after the date of invoice. The cost of not taking cash discounts is the price of the credit.