I know it depends on the site/app, but for a hobbyist, what is the biggest gotcha in a "got super popular over night" situation? If I look at the quotas and overages for low-end plans from the following providers, e.g., it's not obvious to me where the realistic bottlenecks are:
I'd rather my pet project returns 503 after going popular overnight than me footing a huge bill. Especially since my pet projects generally don't generate any revenue anyways. This is the most important feature for me and why I went with GCP.
You know what's going to be cheaper and simpler? Get some vultr VPSes. Maybe one for your web server and one for a PostgresDB, and another for a Redis if you need it.
Done. For 98% of hobbyist projects, a single Vultr $5/month node is probably far more than enough. For 99%, three Vultr $10/month instances (web, DB, cache) is probably enough.
* Firebase Hosting with Firestore
* Cloudflare Workers Sites (using KV)
* Netlify (possibly w/ FaunaDB)