The first time you open an AWS bill, it is genuinely confusing. Dozens of line items, cryptic usage-type codes, numbers that do not match your mental model of what you are running, and no obvious "here is what to do about it." I remember staring at mine trying to figure out why "data transfer" cost anything when I had not transferred anything on purpose. Here is the tour I wish someone had given me: how to read an AWS bill, find the big rocks, and know which numbers actually matter.
Do not start on the Bills page. Start in Cost Explorer.
The raw Bills page is a flat list, accurate but hard to reason about. Cost Explorer is where you actually understand the bill, because it lets you group and filter. Open it and set the view to the current month.
The single most useful thing you can do: group by Service. This instantly shows you the shape of your bill, which handful of services make up most of the cost. Almost every bill is dominated by a few services, and everything else is rounding.
The usual big rocks
