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

− Yearly/Monthly: You pay upfront for the amount of time you expect to use the ECS for. You will need to make sure you have a top-up account with a sufficient balance or have a valid payment method configured first.

− Pay-per-use: You can start using the ECS first and then pay as you go.

− Spot pricing: ECS prices are adjusted gradually based on long-term trends in supply and demand for spot instance capacity.

For details about the three billing modes, see Billing Modes. You can also change the billing mode later if it no longer meets your needs. For details, see Billing Mode Changes.

If you want to ensure resource stability over a certain period of time, yearly/monthly billing is a good choice for the following types of workloads:

• Long-term workloads with stable resource requirements, such as official websites, online malls, and blogs.

• Long-term projects, such as scientific research projects and large-scale events.

• Workloads with predictable traffic bursts, for example, e-commerce promotions or festivals.

• Workloads with high data security requirements.

Pay-per-use billing means you pay nothing up front and are not tied into any contract or commitment.

Pay-per-use billing is good for short-term, bursty, or unpredictable workloads that cannot tolerate any interruptions, such as applications for e-commerce flash sales, temporary testing, and scientific computing.

ECSs that use spot pricing are called spot instances. You need to set a maximum price you are willing to pay for a spot instance. The maximum price must be greater than or equal to the market price but less than or equal to the pay-per-use price.

You can purchase a spot instance at a discounted rate, but there is a trade-off for that reduced cost. If inventory resources are insufficient or the market price exceeds your expected price, the spot instance will be reclaimed.

Compared with pay-per-use and yearly/monthly ECSs, spot instances offer the same performance at a lower price.

Spot instances are a good option if you want to enjoy the same performance at a lower price.

• Applicable scenarios

Image rendering, stateless web services, DNA sequencing, offline analysis, function computing, batch computing, sample analysis, CI/CD, and test.

• Inapplicable scenarios

The applications need to run for a long time or deliver a high level of stability.

Spot instances with a predefined duration are called spot block instances. When purchasing a spot block instance, you need to set a predefined duration and the number of durations. Prices vary depending on the predefined duration.

You can buy spot block instances at an ultra-low price but they may be reclaimed when resources are insufficient.

You can buy a spot block instance at an ultra-low price, but there is a trade-off for that reduced cost. If inventory resources are insufficient, the spot block instance will be reclaimed. Compared with pay-per-use and yearly/monthly ECSs, spot block instances offer the same performance at a lower price.

Spot block instances are a good option if you want to enjoy the same performance at a lower price.

• Applicable scenarios

Image rendering, stateless web services, DNA sequencing, offline analysis, function computing, batch computing, sample analysis, CI/CD, and test.

• Inapplicable scenarios

The applications need to run for a long time or deliver a high level of stability.

You will be billed for instance flavors, images, EVS disks, and EIP bandwidths. For details about the billing factors and formulas for each billed item, see Billing Items.

For more information about the billing samples and the billing for each item, see Billing Examples.

After a yearly/monthly ECS expires, it cannot run properly. If you want to continue using an ECS after it expires, you need to renew the ECS subscription within the specified period. Otherwise, resources, such as vCPUs, memory, and EVS disks, will be automatically released, and data may be lost. You can renew your subscription manually or automatically. For more details, see Subscription Renewal.

You can choose Billing Center > Billing to check the ECS transactions and bills. For details, see Bills.

If there is not a sufficient account balance to pay for your bill and there is no other payment method configured, your account will go into arrears. If you want to continue using your cloud services, you will need to top up your account in a timely manner. For details, see Arrears.

If you no longer need to use your cloud service, you can unsubscribe from or delete it to stop the billing. For details, see Billing Termination.