Its been about 18 months since I was at an AWS-heavy shop. We used Netflix Ice (open source) to do cost reporting. We also heavily leaned on resource tagging to be able to report on segmentation - what teams were using resources, if it was dev, test, or prod etc. Tagging was crucial to managing costs for medium/large organizations and we spent a lot of time ensuring everyone was tagging their resources properly. I also made a one-liner change to Ice so that it would group untagged resources together so we could do reporting on how well we were tagging resources.
1. They have really good reporting options. You can see how much you're spending day-by-day and how much your estimated monthly total will be. You can break it down by service, or even by account with consolidated billing.<p>2. They have built-in billing alerts. You can get notified if your spend in any particular category is greater than some threshold.<p>3. We use a 3rd party service (Cloudability) to help with cost tracking and RI allocations. There are several other companies that do the same, and depending on your total AWS bill they have more or less automation available to you.
Cloudabilty it awesome.<p>AWS' Billing dashboard is also great for a quick view. The report I use most is one I created that is the "Daily Cost per API Operation". Do the "Daily costs" report then group by API operation. I then view it by day (instead of month) for the last 3 cal months as a stacked bar graph.<p>I also have a CloudWatch alarm set to trigger at a certain spend. That alarm should trigger around the same day of each month. That way if it triggers 7 (or whatever) days before expected, I know we may have a problem.
Cloudability as primary.<p>Cost Explorer as secondary or more detailed views.<p>We're mostly done migrating to a subaccount per squad (or even service) model, which means there's a useful report in cost explorer on the micro level. (We started in one massive, central, shared account and tried to get by with tagging; that was largely a failure on the tagging front, but it also made it quite difficult to ensure that you had all the access and freedom you needed without inadvertently having more access than you wanted to someone else's stuff.)