If you need more than the free tier of resources in your organization, you can set up billing. When you set up billing you can also buy other features offered by Microsoft or other companies.
The free tier includes the following aspects:
All charges appear on your monthly Azure bill. Azure supports payment by credit card and invoiced billing through the Enterprise Agreement (EA), Cloud Solution Providers (CSP), and more.
During your first purchase for your organization, you're prompted to select the Azure subscription to use for billing. The subscription can be part of your Enterprise Agreement, Pay-As-You-Go, Cloud Solution Provider (CSP), or other types of Azure subscriptions. All services get billed via Azure. You aren't required to pay for or use any other Azure services.
To estimate costs for Azure DevOps, see the Pricing calculator or the Azure DevOps pricing page.
See the following articles for information about the paid services offered by Microsoft:
The Azure DevOps cloud-based load testing service is deprecated, but Azure Load Testing remains available. This fully managed load testing service allows you to generate high-scale load using your existing Apache JMeter scripts. For more information, see What is Azure Load Testing? and Changes to load test functionality in Visual Studio and cloud load testing in Azure DevOps.