@Mirella Pellizzon Petruci Welcome to Microsoft Q&A forums.
The cost associated with Outbound Data Transfer (Internet Egress) is minimal.
Unless you are transferring Terabytes of data it is not going to be significant.
Internet Egress of 5GB/Month is free per subscription.
Beyond that, the charges are $0.08 per GB (in North America and Europe).
For a complete list of charges by region, please check the Internet Egress section on this page.
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