Select the region(s) where you want to setup

Select the region(s) you want to use and disable the use of other regions in multiple accounts using AWS Organizations through Service Control Policies

Documentation site with policy examples

AWS Regions

Use of AWS Organizations service as well as Service Control Policies are free.

https://aws.amazon.com/about-aws/global-infrastructure/regions_az/

Pricing

AWS Organizations service and its Service Control Policies are free to use.