Hello @Amauri Rodrigues ,
While we can't answer billing questions here we can provide resources that will help you better understand what different charges may be. You can speak with billing directly if you want, however, by going to the portal:
In the Azure portal, you can open a billing support request by going to Help + support > New support request > Billing and then complete the wizard.
When trying to understand costs, there are 2 tools I typically rely on. The first is the Azure Pricing Calculator:
https://azure.microsoft.com/en-us/pricing/calculator/
This gives you an estimate of what charges will be before you create your resource in Azure.
The second tool is Cost analysis which you can find under Cost Management for your resource group in the portal (or "View Cost" on a resource):
https://learn.microsoft.com/en-us/azure/cost-management-billing/costs/quick-acm-cost-analysis
This is a great way to check your daily costs with a full breakdown of what you are being charged for (including network and storage costs).
As far as the Azure free account, you can find the details of what is covered here:
https://azure.microsoft.com/en-us/free/
You will have 30 days to use your $200 Azure credit in addition to 12 months of popular services for free (including 750 hours of Linux B1 burstable virtual machines) but be sure to check the offer page for the current terms.