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 data storage.
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.

In a bill, you can check wether an item is billed on a pay-per-use or yearly/monthly (resource packages) basis.

In the bucket list, copy the name of the bucket whose bill you want to view.
On the right of the top navigation bar, click Billing & Costs.
Choose a billing cycle and specify a display dimension (Usage by default).
Select Resource ID as the search criteria, enter the bucket name copied in 1, and click the icon.

You can also click above the list to export the bill details.
In the Billing Mode column of the bill, check the billing mode of an item.