Terracost is an open-source Go library for estimating the cost of Terraform-managed infrastructure before deployment. It ingests prices from cloud providers, currently AWS, Google and AzureRM, and applies them to the resources in a Terraform plan. According to its README it is meant to be imported into other programs rather than used as a standalone command-line tool. Teams use it to build cost estimates into their own pipelines or platforms. It is a European alternative to commercial or US-based tools that estimate costs from Terraform code.
Terracost is MIT-licensed and maintained by Cycloid, a French company headquartered in Paris. No owner outside France has been identified. You run the library yourself, with a MySQL-compatible database and internet access to fetch prices; the vendor hosts no service for your data. Your Terraform plans therefore stay within the infrastructure you choose. There is no US parent company and so no CLOUD Act exposure through the vendor.