Hi Benedikt Pittl:
Thanks for reaching out to Microsoft Q&A.
Here is the explanation from MS on how the pricing is configured for blob storage.
Pricing for inventory is based on the number of blobs and containers that are scanned during the billing period. The Azure Blob Storage pricing page shows the price per one million objects scanned. For example, if the price to scan one million objects is $0.003, your account contains three million objects, and you produce four reports in a month, then your bill would be 4 * 3 * $0.003 = $0.036. After inventory files are created, additional standard data storage and operations charges will be incurred for storing, reading, and writing the inventory-generated files in the account. After an inventory report is complete, additional standard data storage and operations charges are incurred for storing, reading, and writing the inventory report in the storage account.
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