Azure Firewall is a managed, cloud-based network security service that protects your Azure Virtual Network resources. It's a fully stateful firewall as a service with built-in high availability and unrestricted cloud scalability.

As I haired from a few customers that Azure firewall is a little bit expensive! and some of them they don't have a budget for test/dev environment,as it cost (approximately $100 monthly, per appliance). This price gets compounded if you need to deploy multiple Azure Firewall appliances per regional VNet

In this post we will explain how to deploy FortiGate NGFW for Azure, you can deploy the FortiGate for Azure as a virtual appliance in Azure cloud (infrastructure as a service)