Yes, Azure functions provide free grants(1 million requests and 4,00,000 GB-s of resource) which applies to paid, consumption subscriptions only per month.
Once the Azure functions are developed and deployed to azure, then you can pay per use pricing model. While creating azure function, you must choose a hosting plan for your app. There are 3 types of pricing plans.
- Consumption Plan - is billed based on per-second resource consumption and executions.
- Dedicate(App Service) Plan - Runs like your web apps. If the app service plan is shared between your applications and functions there is no additional cost for functions run.
- Premium Plan - It contains Pre-warmed instances that are always readily available to respond immediately. Also, it contains VNET connectivity for security. In this plan, you pay for Pre-warmed instances and any additional instance which you use to scale your app in and out.
Consumption and Premium plan automatically scale out whenever there is a need by adding compute power and scale in when the code is stopped running. Also, both plans provide a monthly free grant of 1 million requests and 4,00,000 GB-s of resource consumption per month per subscription in pay-as-you-go pricing across all function apps in that subscription.
In the App Service plan, your app does not scale automatically. Also, you must enable Always on setting so that your function app runs correctly.
Note: A storage account is created by default with each Functions app. The storage account is not included in the free grant.