Hi Jeff,
The company has an enterprise agreement with Microsoft, as many do, where the pricing is baked-in for all that they order off the menu.
That being said, as I recall, the most expensive configuration of the constellation, are the two NC6 Standard set-ups for our multi-user remote desktops. Cost-wise, however, the capacity for handling users up in Azure, and the advantages in performance gains (Azure to Azure vs. on-premise desktops to Azure) probably could be calculated in time-cost-efficiency ROI. Up in Azure, everything is faster. Mixing Azure with on-premise, you have bandwidth, I/O, etc. differences and the network must be super-speedy and optimized if used in this way.
The server, and the database server VM's - the DS12_V2's (4 of these, 2 for the ArcGIS Server's VM, 2 for the SQL-DB's) were the next in terms in cost. The portals - the A4_V2's (two of these) are "lightweights" by comparison in cost. I think that the NC6 was just over $1K/mo each - and there are options for scaling, and putting these VM's into "heartbeat" if you have nothing going on, which apparently reduces the cost considerably, per month.
At $1K/month supporting 5 users, annualized, this is probably a good use of dollars, since you have no hardware left to amortize from the accounting perspective, nor do you have to get rid of old machinery and re-buy a workstation every couple of years to keep up with what resources are truly required. It depends on the perspective of the IT organization as to what they want to manage - "the cloud" vs. "assets in the server room, and in offices". All entail costs of some sort.
I also know that Microsoft updates its pricing on a regular basis for Azure's offerings, as well, they continue to build more configurations that are available. I also know that Esri have just pushed out some new info about what's available with the Esri-Azure certified configs offered.
Here is the pricing calculator off Microsoft's site that is helpful when planning: Pricing Calculator | Microsoft Azure - there is also that same link on the Esri landing page for Azure: ArcGIS Enterprise on Microsoft Azure—ArcGIS Enterprise | ArcGIS Enterprise on the Esri site.
I'm no expert, but I am in this with sleeves rolled up, day to day, and we feel pretty good, still, about using Azure; We are getting ready to upgrade to 10.6 ArcGIS Enterprise to deal with some 10.5 issues that are resolved in the dot release. The lovely thing about Azure is that you can change without buying hardware, which I think is one of the major attractions.
Our users seem to like it, as well. And, as with anything new, we learn something every day.
Hope this helps.
