Matt, we dedicate Storage Accounts to given teams/environments we then add the Scalr Cost Center TAG on the Storage Account. We do a final bill using the Azure Excel Export, this then covers all items TAG'ed by Scalr and the Storage Account Manually TAG'ed.
The Scalr Cost Analytics gives users a very good understand of what their bill will end of being say 90%.
One thing to note is that when you delete a VM it doesn't delete the VHD. This is the same in Scalr or direct in Azure, so unless you do a clean up on a regular basis the Storage Account Costs will go up for no obvious reason. A simple PowerShell script will clean these orphaned VHD's up