Into "Cost Explorer Monthly costs by service" report I saw $300 for S3 for certain month. But when I tried to drill-down into the bill for this month, I saw just $4 for the "Simple Storage Service". So I'm not sure I understand how I can investigate S3 cost.
TIA, Vitaly
Use the AWS Cost Explorer. Log into your account then use this link, or navigate to "my billing dashboard".
It's a bit odd to get into. You have to click "Cost Explorer" on the top left of the menu bar, then click "launch cost explorer" on the right so it opens a window, then you click "cost explorer" top left again. Really weird.
Once it actually loads up you can choose to filter by server (right hand side), then you can sort by usage type (in the middle above the graph). Details appear under the graph. It takes some playing around to get good at it.
To decode the screenshot below:
You can see in July there were a lot of uploads to Glacier Deep Archive, which increased the bill.