service charge
noun [ C ] uk/ˈsɜː.vɪs ˌtʃɑːdʒ/ us/ˈsɝː.vɪs ˌtʃɑːrdʒ/
服务费
an amount of money added to the basic price of something to pay for the cost of dealing with the customer
If you order the tickets by phone you have to pay a $2 service charge as well as $13.50 for each ticket. 如果通过电话订票，除每张票13.5美元外，还须支付每张2美元的服务费。