Pulumi is free: "Pulumi is true open source, uses the Apache 2.0 license, and does not and never will depend on BSL-licensed software in any way, HashiCorp owned or otherwise." (https://www.pulumi.com/blog/pulumi-hearts-opensource/)
Pulumi Cloud (the SaaS offering) is (mostly) not free. There is a free tier for individuals/companies with minimal needs.
You may happily use Pulumi and manage your own state files, for free, and open source.
I yet have to read/hear about somebody self-hosting Pulumi. It lacks the huge Terraform ecosystem and without the paid cloud offering, it's pretty rudimentary.
Pulumi Cloud (the SaaS offering) is (mostly) not free. There is a free tier for individuals/companies with minimal needs.
You may happily use Pulumi and manage your own state files, for free, and open source.