Azure Pricing

https://azure.microsoft.com/en-us/pricing/details/managed-disks/

For P20 disks and smaller, credit-based bursting is enabled by default with no additional costs. You can boost your performance up to 3,500 IOPS and 170 MB/s for up to 30 min to handle spiky traffic, process batch jobs, and improve boot times.

For P30 disks and larger, you will be charged a monthly enablement fee of $24.576 to enable on-demand bursting and a burst transaction fee of $0.005 per 10,000 IOs for additional IOPS. You can boost your performance up to 30,000 IOPS and 1,000 MB/s at any point in time