Which service is best for small scale non-static web hosting?

I've read through pricing plans of many providers, including aws, gcp, digital ocean, and a myriad of other web hosting providers that advertise as being budget friendly that were new to me. I'm aware of free options such as heroku, but would rather just start with a service I won't have to migrate from for a long time. I plan to host a few personal projects which require websocket connections, and some which require occasional heavy computing.

I'm fine with any reasonable monthly cost, but I'd like to be secure in knowing the maximum charge per month unless I explicitly approve more expenditure. Lots of services leave it pretty unclear as to whether the site will just go down upon exceeding monthly resource limits, or if it'll stay up and continue billing, or if it just starts billing for the next month early, etc.