There is no direct answer to it as there are various factors involved like configurations you use while copying the data.
Do visit the ADF Pricing page - https://azure.microsoft.com/en-us/pricing/details/data-factory/data-pipeline/
Azure pricing calculator to estimate price - https://azure.microsoft.com/en-in/pricing/calculator/
Below activity that is configured to copy files from one Azure storage to another. It shows the tooltip that helps you with cost calculation.
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Please don't forget to Accept Answer and Up-vote if the response helped -- Vaibhav