AWS Identity and Access Management (IAM)
It allows you to administer access to AWS services and resources safely. With the use of IAM, you can make and administer AWS users and groups, and utilize permissions to let and refute their access to AWS resources.
Of your AWS account IAM is a feature provide at no extra cost. You will have to pay only for utilization of other AWS services by your users.
To begin with the utilization of IAM, or if with AWS you have previously registered, go to the AWS Management Console and begin with these IAM Best Practices.