Cost of frade Credit a. If a firm buys under terms of 3/15, net 45 , but actually pays on the 20 th day and still takes the discount, what is the nominal cost of its nonfree trade credit? Nominal cost of nonfree trade credit = b. The firm recelves credit than it would if it paid within 15 days. Cost of Trade Credit a. If a firm buys under terms of 3/15, net 45 , but actually pays on the 20 th day and still takes the discount, what is the nominal cost of its nonfree trade credit? Nominal cost of non credit = b. The firm receives credit than it would if it paid within 15 days