Null_resource Powershell

So currently the Azure provider does not include the ability to create Cost alerts for resources (feature is in preview). The azure powershell module does provide methods and cmdlets to create and update them though.

I am trying to fill the capability gap by using a powershell script to create the budget and notifications that we require but I was wondering if anyone had any best practice advice for things like this? I am guessing that the budget and notification will not be in the state as they are essentially created outside of terraform which means my script will probably fail trying to create it on each run. Should the logic to handle this be placed in the script or is the logic better placed in a trigger before script execution and base it off a variable in the module we call perhaps?