I'm sure my scale is many magnitudes smaller but as a solo developer/founder I ran into this same issue recently as I've been creating more PRs than normal and also increasing my GH Actions usage for things like LLM review and just more unit/e2e/etc tests.

Last month I ran up $45 of overage spending (yes, I know, I know, this is tiny but for me it's not) and decided to make use of my homelab that was effectively twiddling it's thumbs most of time.

I settled on small VMs that I delete and restore from a snapshot after every run and it's worked out great so far. They only take up a tiny bit of ram when they are first started up and only take more from the system when they pick up a job. Even though each worker can use 6GB they rarely do and I can run 6-8 of these on my box safely (even if all use 6GB).

I used a custom image containing only what I needed and that's worked really well for me so far and it's easy to add more to it if needed in the future.

After this change I went from spending $2-4/day to <$0.25 (I left a few very small tasks on GH Actions).

It's not always the right call and for paid workers I'd reach for WarpBuild or similar most of the time (WarpBuild still runs my deploys/iOS builds) but for all the PR-check actions, those work just fine on my local server.

With Claude it was super easy to get set up. It's not a very complicated process at all but I was always unsure of the ROI for the time to set it up and tune it. After the overage bill I figured I'd try it out and it worked out even better than I had hoped for (including having a number of the jobs run faster since my workers were bigger/better/faster/stronger than the default GH worker, no surprise there). I even considered running 1-2 VMs on my MBP as well so it could pick up some of the load.

All that said, if your GH Actions bill is going up (which it probably is), I can highly recommend looking into running your own workers for at least part of the load.