AWS platform provides a set of tools to help monitor and analyze your costs. These include the AWS TCO Calculator, the simple monthly calculator (described in Chapter 2, Designing Cloud Applications – An Architect’s Perspective), AWS billing console, which shows you an itemized bill, and AWS Cost Explorer, which gives you costs trends information across different time periods.
EC2, S3, CloudFront, and so on offer volume pricing tiers at lower price points based on usage. If the payer account combines usage from all the subaccounts, then you can get these discounts automatically using consolidated billing (with no additional effort involved).
The TCO calculator can be used to compare on-premise versus on-cloud costs. The AWS simple monthly calculator is a useful tool to select the various AWS services and options to compute your costs. AWS Trusted Advisor provides an automated way to save money. The tool comes free with business and enterprise support subscriptions. It scans your AWS infrastructure and identifies targets for further savings by generating a cost optimization report. It will tell you about idle instances that you may want to shut down and also the amounts you will be able to save by switching to reserved instances.
You can use the AWS billing console to drill down deeper into the AWS bill to see an itemized list of components and their costs. This can help us identify optimization targets. You can also set AWS billing alerts, which send you automatic notifications when your bill hits some preset threshold. These thresholds can also be used for auto scaling where you can shut down instances, automatically, if your bill reaches a certain level. You can also enable detailed billing to break down costs by hour, day, or month; or by each account. AWS will publish these reports as CSV files and store them to a S3 bucket.
There are several third-party open source (for example, Netflix ICE) and commercial tools (for example, Cloudability). These tools provide cost and usage reporting, information related to accounts, and comparison across time periods and underutilized instances.