Events are available with all Standard Plans at no extra charge, as long as CloudSploit processes fewer than 500 thousand events per month. However, AWS charges for the resources that are created in your account.
If you enabled Events prior to 12/2019:
Specifically, you will be charged for SNS endpoints ($0.50/region/million calls), and CloudWatch Events delivery ($1.00/region/million calls). 99% of users will see less than a $5 increase from AWS per month.
If you enabled Events after 12/2019:
CloudSploit utilizes an AWS CloudTrail to send write-level API activity to its S3 bucket for processing. AWS charges $2 per 100,000 CloudTrail events.