[Roark66]

There are no billing limits, but there are resource limits set by AWS upfront. I had to create many support cases to raise this or that limit. (for example we had a limit if 100 concurrent lambda workers, then 2.5k if I remember correctly). Some number of active ec2s, some total TB of storage etc. We were hitting those limits pretty frequently despite spending over £50k per month with them (mostly dev and test services).

[toomanybeersies]

I'm pretty sure that AWS' service quotas exist more as a guardrail to prevent customers from accidentally spinning up 1000 instances instead of 10, which would not only leave you with an eye-watering bill, but affect resource availability for other customers.

They're usually quite happy to increate the quote if you contact support.

[whoknew1122]

Most limits exist within what AWS has determined is 'normal' usage. Once you pass that, you can request a service limit increase.

Service limit increases are typically only denied when raising the limit would negatively impact the availability of the service (noisy neighbor issues, for example), or if the customer is needing a limit increase because they're trying to use the service in a way it wasn't designed.