There are some new tools worth learning about if moving from capital expenditures to subscription models are one of the many financial questions you have regarding this new cloud world. 

https://azure.microsoft.com/en-us/blog/azure-cost-management-now-general-availability-for-enterprise-agreements-and-more/  

"As enterprises accelerate cloud adoption, it is becoming increasingly important to manage cloud costs across the organization. Last September, we announced the public preview of a comprehensive native cost management solution for enterprise customers. We are now excited to announce the general availability (GA) of Azure Cost Management experience that helps organizations visualize, manage, and optimize costs across Azure."