Pay-As-You-Go instances require no up-front payment and are only charged based on usage. Resources can be scaled to suit the needs of your business. Pay-as-you-go EIP instances can be released at any time, and after release, the current hour's bill will be issued and deducted on the next hour.
Compared to pay-as-you-go instances, subscription instances have a lower price point which will help you to reserve your resources. Subscription instances are ideal for users requiring long-term resources in large numbers.