Azure provides various Hosting Plans with various Hardware & Price mix. We can select a Plan well suited for our purpose.
FREE Plan – F1
This plan is meant for Development Or Testing purposes.
It has restriction of 60 minutes/day compute.
This is Free!
But the hardware will be on shared basis.
Custom Domains are available with D1 and B1 plans.
Production Plans
Production level hosting plans are starting with S1.
S1 supports Auto Scalability up to 10 instances, Traffic Manager etc.
P1v1 supports Auto Scalability up to 20 instances.
Isolated Plans
These plans runs in their own network in Single Tenancy mode.
Note
These plan includes the IaaS + PaaS components of hardware, operating system etc.
References
https://azure.microsoft.com/en-in/pricing/details/app-service/windows/