My company was part of a partner acceleration program, however you can apply to be part of the Google Cloud for Startups program here[1], without needing to be in an accelerator.
A current happy Google Cloud customer here, who also received the Startup credits.
When you have credits on your account none of the alerts or budgets work (at least they didn't when I was using it).
The only thing you could do is look at your figures daily and plan/scale based on the running total.