Azure Functions pricing
Azure Functions has three kinds of pricing plans. Choose the one that best fits your needs:
Consumption plan: Azure provides all of the necessary computational resources. You don't have to worry about resource management, and only pay for the time that your code runs.
Premium plan: You specify a number of pre-warmed instances that are always online and ready to immediately respond. When your function runs, Azure provides any additional computational resources that are needed. You pay for the pre-warmed instances running continuously and any additional instances you use as Azure scales your app in and out.
App Service plan: Run your functions just like your web apps. If you use App Service for your other applications, your functions can run on the same plan at no additional cost.