Hi @Pradeepa ,
the Azure Data Manager for Energy in the Azure Marketplace is not listed as a free service here:
In the FAQ of Azure free services you will find this information related to Azure Marketplace services:
This might be the reason why you are charged for using this service.
it might be an option to open a support case with Microsoft Azure support for clarification.
Azure Billing and Subscription support is offered by Microsoft by no cost and it's for free.
Source: Azure Support plans
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Regards
Andreas Baumgarten