https://docs.microsoft.com/en-us/azure/azure-monitor/insights/vminsights-overview
“There’s no direct cost for Azure Monitor for VMs, but you’re charged for its activity in the Log Analytics workspace. Based on the pricing that’s published on the Azure Monitor pricing page, Azure Monitor for VMs is billed for:”
Data ingested from agents and stored in the workspace.
Alert rules based on log and health data.
Notifications sent from alert rules.
Ref MS
Market (SaaS)