Pay-as-you-go is a payment model for cloud services that involves paying for goods or services before they are used. When a customer needs a service, he sends an electronic payment to the service provider and gets access to the resources and products he is interested in.
The pay-as-you-go model avoids entering into long-term legal contracts, which can be convenient, for example, when a company wants to test a service before switching to a more expensive tariff plan or entering into a long-term agreement.
In particular, such large cloud services as Amazon Web Services (AWS) and Microsoft Azure provide their services under the pay-as-you-go model.