Amazon CloudWatch announces detailed billing to CloudWatch Logs. You can now get usage and cost per log group. You can also add tags on your log groups to get a fine-grained view on cost for logs across business dimension such as cost center, application name, AWS services such as Lambda, CloudTrail, ECS, and other. Up to 50 tags can be added to each log group.
To learn more about this feature, click here. To know more about CloudWatch Logs, visit the CloudWatch Logs product page.