ec2-cost-calculate.rb was created to easily sum the total of instances running in one or all regions. The typical use would be to run the ec2-cost-calculate.rb script and then import into a spreadsheet application for further analysis. Another use would be to run the ec2-cost-calculate.rb script with cron, producing a weekly output file (an example of this: `echo "0 0 * * 0 ec2-user /home/ec2-user/ec2-cost-calculate.rb --period day --region all --output file --file /home/ec2-user/ec2-cost-report`date +"%Y%m%d"`.txt" > /etc/cron.d/ec2-cost-calculate`).
the file "ec2cc - IAM User Required Permissions.json" contains the permissions required to run ec2-cost-calculate.rb in with the "Least Permissions" required as of 2012-11-11.