You will be billed for your use of SAS Viya Pay-As-You-Go by Microsoft and those charges will be visible in the Azure Portal. There are actually two places that you need to go to see these costs, one for the software costs and another for the infrastructure costs.
1. If you do a "cost analysis" on the resource group where you deployed the managed application, you can get the SAS Unit costs:
2. If you click on the Managed Application and then select the "Managed Resource Group", and do a "Cost Analysis" at this level you can get the infrastructure cost breakdown:
Hope that helps!
Chris