Today, we are introducing a Free Tier for VPC IP Address Manager (IPAM) that helps you get started with IP address management tasks. It includes features for public IP address planning, and also includes Public IP Insights which now provides a unified view of your public IPv4 usage. If you have an existing IPAM, it will now become Advanced Tier, and you can continue using its features without any change in IPAM cost.
Source:: Amazon AWS