I think backblaze does it well. You can set limits for each type of API transaction and you receive email and sms notification when you get close to the cutoff

I think backblaze does it well. You can set limits for each type of API transaction and you receive email and sms notification when you get close to the cutoff limit (70% and 90% IIRC). You have a page with all the costs and how close you're to the limit if any. 2FA was also straightforward to setup. If your account is compromised the limits can still be lifted but there is limited interest in compromising a backblaze account in the first place and the 2FA makes it unlikely. I'm the sysadmin for a small nonprofit so my organization qualify for the $3500 yearly azure credits but the inability to set spending limits makes me not use azure. If I make a mistake or worse an admin account is compromised the azure bill is potentially infinite. With azure I think you can mitigate the issue somewhat by having a superAdmin account without limits and set quotas for everything else but I still don't feel at ease with that. My organization is a music festival so the infrastructure really has to work and not stop one day per year. I can keep an eye on everything during the festival and monitor spending. If things stop not during the festival people are a bit annoyed until I can look into the issue but nothing bad happens. In a perfect world I'd like to have a way to setup a limit where you need to go through support to increase it. I'd really pay for that. I think it's really too easy to receive a nasty surprise bill.