customer's free credit balance

例句：

1. 1. The company offers a 10% discount on all purchases made by customers.
   该公司对所有顾客购买的商品提供10%的折扣。
2. 2.The bank has a customer's free credit balance of $500.
   银行有一笔客户免费的信用余额，金额为500美元。
3. 3.The customer's free credit balance is used to cover the cost of goods sold.
   客户的免费信用余额用于支付销售商品的成本。