I don't have a credit card on file, I'm not sure how they are going get paid if my balance goes negative.

Also: https://support.bunny.net/hc/en-us/articles/360000235911-How...

But yes, other services will run until your account is dry, then it gets suspended. You can't set a spend limit on your scripts without it taking down the whole account. You can't do cost optimization, but at least you are protected from going bankrupt.