After you specify the instance type and network configurations, you can estimate costs based on the factors such as billing methods, regions, images, networks, and the number of instances.
The available billing methods include subscription, pay-as-you-go, preemptible instances, and reserved instances. For more information, see Subscription and pay-as-you-go, Preemptible instances, and Reserved Instances.
Subscription is a type of pre-payment, which indicates that instances are available only after you make the required payment. The billing cycle is measured on the weekly, monthly, or yearly basis. The billing method is applicable to the services that run for 24 hours a day and 7 days a week, such as Web services.
Pay-as-you-go is a type of post-payment, which indicates that you can make the payment after using the service. You are billed by second. The unit price of instances is provided in USD/hour. The billing method is applicable to the business apps or services that have traffic spikes, such as temporary expansion, temporary tests, and scientific computing.
- Preemptible instances
To reduce costs of using ECS services, you can use preemptible instances. Preemptible instances are on-demand instances for which you need to set the maximum prices (in USD/hour) for bids. If your bid prices are higher than the current market prices, the preemptible instances are available for your use. You are billed for the instances at the market prices.
- Reserved instances
Reserved instances are coupons that can be used to purchase one or more pay-as-you-go instances at discounted prices. You can also use reserved instances to reserve instance resources for later use. You cannot use reserved instances to pay for preemptible instances. Compared with subscription, a combination of reserved instances and pay-as-you-go is more flexible and cost-effective.
The advantages of each billing method vary with different ECS types. For more information, see ECS pricing.
- The region of the instance and the geographical location of your target users
- The relationship between ECS and other Alibaba Cloud services
- The prices of the resources in the target region
- Special requirements such as compliance requirements (For example, when you use ECS instances as Web servers in mainland China, you must file the business licenses for record.)
Quantity of ECS instances
If you purchase more ECS instances, the cost rises.
The prices of instances vary with different image types. For more information about the billing methods, see Image overview.
After completing the overall network planning, you must select a specified VPC and vSwitch. VPCs and vSwitches are available for free.
- You can assign a public IP address to the instance as follows: Select Assign Public IP Address and specify the Internet bandwidth. You are charged based on the bandwidth you have specified. For more information about the billing of the Internet bandwidth, see Public bandwidth. If you specify 0 Mbps for the bandwidth, no bandwidth is available.
Note The public IP address assigned to an ECS instance cannot be unbound from the instance.
- Elastic IP Address (EIP) provides a more flexible solution compared with public IP addresses. We recommend that you assign an EIP to the instance. For more information about the billing of EIP, see Billing overview.