CloudCheckr provides several reports that not only analyze your EC2 costs, but also provides recommendations on ways to save money.
EC2 Cost Utilization Report – shows how much CPU is utilized by the instances running within EC2, based on the data available in CloudWatch. This report will show you whether your instances are under utilized, and should be downsized.
EC2 Cost Warnings Report – looks at your EC2 deployment and highlights items that are not in use, but are being invoiced by AWS including un-attached EBS Volumes, Load Balancers and Elastic IPs.
EC2 Cost Comparison Report – shows how much you would spend, were you to move each of your EC2 instances to the various pricing types in AWS. It shows how much you would pay for an instance were it spot, on-demand, 1 year reservation, or 3 year reservation (including pricing for light, medium, and heavy utilization).
EC2 Cost Recommendation Report – looks at each running On-Demand instance and suggests that you convert the instance to different price types, depending on how long you plan on utilizing the instance.
EC2 Reserved Instances Reports – shows how many Reserved Instance have been purchased, and alerts you to any that are not being used.