I recently got annoyed with the amount I was paying on actions for a single repo. And decided to use a Mac mini that I had lying around to become the sole self-hosted runner for that repository instead.
It was ridiculously easy to set up, reduced my issues with GitHub significantly and the mini will literally pay for itself 3-4x over this year with the $$$ I'm saving not paying for GH actions.
The most surprising part for me was not the cost savings, but that all my workflow runtimes went down by about 70-80%.
If you're still using github workflows with your own action runner, you are still susceptible.
You can use Kubernetes with Kaniko or Docker-in-Docker or rootless Docker for building stuff too. I think that's much cheaper in an org context. The amount of CI we run, we have saved countless dollars.
We were thinking about opensourcing our flows.