Overview

There are yearly/monthly and pay-per-use billing modes. Each one has different advantages and disadvantages.

Yearly/Monthly is a prepaid billing. You pay in advance for a subscription term, and in exchange, you get a discounted rate. The longer the subscription term, the bigger the discount. Yearly/Monthly billing is a good option for long-term, stable services.
Pay-per-use is a postpaid billing mode. You pay as you go and just pay for what you use. The DRS usage is calculated by the second but billed every hour. This mode allows you to adjust resource usage easily. You do not need to prepare resources in advance, and will not have excessive or insufficient preset resources.

Table 1 lists the differences between the two billing modes.

**Table 1** Billing modes
Billing Mode	Yearly/Monthly	Pay-per-use
Payment	Prepaid	Postpaid
Billing Method	Billed by the subscription term you purchase	Calculated by the second but billed every hour
Billed Items	Configuration fee and EIP fee	Configuration fee and EIP fee
Billing Start	Upon task start	Upon task start
Changing the Billing Mode	Yearly/Monthly cannot be changed to pay-per-use.	Pay-per-use can be changed to yearly/monthly. Pay-per-Use to Yearly/Monthly
Changing the Specifications	Supported	Supported
Application Scenarios	Recommended for resources expected to be in use long-term. A cost-effective option for scenarios where the resource usage duration is predictable.	Recommended when the resource demands are likely to fluctuate and you want more flexibility.