You can collect and send logs for Azure Storage to Azure Monitor log analytics workspaces, Azure Event Hubs, Azure Storage, and select Marketplace partners.
The pricing model for diagnostic settings is in effect for Azure Storage logs. Sending logs to Azure Storage, Azure Event Hubs, or Marketplace partners will incur a charge per GB sent by diagnostic settings and independently of any costs charged by the destination.
Read the Azure Monitor pricing page under Platform Logs to learn more about the pricing model and Azure Storage documentation to learn more details about the announcement. Note: Changes to the Portal UX and documentation to remove "preview" designation for this feature will follow over the next few weeks