Overview

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

Yearly/Monthly is a prepaid billing mode. 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 OBS usage is calculated by the second but billed every hour. Pay-per-use billing is a good option for scenarios where there are sudden traffic bursts, such as e-commerce promotions.

Table 1 lists the differences between these billing modes.

**Table 1** Differences between billing modes
Billing Mode	Yearly/monthly	Pay-per-use
Payment	Prepaid Billed by the subscription term you purchase	Postpaid Billed by the actual OBS usage
Billed Usage Period	Hour	Hour
Billing Items	Single-AZ Standard storage Multi-AZ Standard storage Single-AZ Archive storage Outbound Internet traffic Pull traffic Cross-region replication traffic	All OBS items can be billed on a pay-per-use basis. For details, see Pay-per-Use Billing.
Billing Mode Change	Yearly/Monthly can be changed to pay-per-use. The change takes effect only after the yearly/monthly subscription expires. Billing Mode Changes	Pay-per-use can be changed to yearly/monthly. Billing Mode Changes
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.	Good for short-term, bursty, or unpredictable workloads that cannot tolerate any interruptions.