Each App Service plan tier supports a different number of deployment slots. There's no additional charge for using deployment slots. To find out the number of slots your app's tier supports, see App Service limits.
However, note that the resources used by the cloned deployment slot will still count towards the resource usage of the original App Service plan. This means that if you have a limited amount of resources available in your App Service plan, creating multiple deployment slots could potentially impact the performance of your app.
Also, note that if you configure the cloned deployment slot to use additional resources (such as a larger VM size or more instances), this could result in additional costs. So, it's important to monitor your resource usage and adjust your App Service plan accordingly to avoid unexpected charges.
Hence, cloning an Azure App Service deployment slot itself does not incur any additional cost, but the resources used by the cloned slot will still count towards the resource usage of the original App Service plan.
You maybe interested to know about the following questions, kindly take a look at the FAQs from this doc: Azure App Service plan overview
- Should I put an app in a new plan or an existing plan?
- How much does my App Service plan cost?
- What if my app needs more capabilities or features?
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