Traditional billing methods in the brick-and-mortar paradigms are costly and involve generating invoices, stuffing envelopes, affixing proper postage to the envelopes, and sending the invoices to the customers.

• 在传统的实体商店模式下，其支付方式代价高昂，因为要开具发票，把发票装入信封，贴足邮票，最后将收据寄给顾客。