ExpressRoute Circuit Fee (10 Gbps):

Unlimited Data Plan: $88,000 per month for Zone 2 (Europe) locations​ (Azure)​.

Additional Costs:

Global Reach Add-On (if needed for connecting multiple data centers): $0.055 per GB for outbound data transfer within Zone 2​ (Azure)​.
Virtual Network Gateway: Depending on the type, this can be up to $1.36 per hour for the Ultra Performance Gateway, which supports 10 Gbps bandwidth​ .

Breakdown:

ExpressRoute Circuit Fee: $88,000 per month.
Virtual Network Gateway:
Ultra Performance Gateway: $1.36 per hour * 730 hours (approx. 1 month) = $992.80 per month.

Total Estimated Monthly Cost:

ExpressRoute Circuit Fee: $88,000
Virtual Network Gateway: $992.80

Total: $88,992.80 per month

Please note that these are approximate costs and actual expenses might vary based on additional factors like specific data transfer volumes, additional add-ons, and regional pricing adjustments. For a more precise estimate, you can use the Azure Pricing Calculator and input the specific details of your setup.