Earlier quoted context omitted.
They still run the whole orchestration. If you don't want to pay, you'd have to not use GitHub Actions at all, maybe by using their API to test new commits and PRs and mark them as failed or passed.
One problem is that GitHub Actions isn't good. It's not like you're happily paying for some top tier "orchestration". It's there and integrated, which does make it convenient, but any price on this piece of garbage makes switching/self-hosting something to seriously consider.
Nothing kills morale faster than wrenching on the unreliable piece of infrastructure everyone hates. Every time I see an alert in slack github is having issues with actions (again) all I think is, "I'm glad that isn't me" and go about my day