That 64 core server is probably sitting nearly idle most of the time. You don’t just spin up big systems on AWS and leave them idle. The whole point of cloud computing is the on-demand scalability.
You can basically spend nothing until a request comes in, and most hobby projects are low traffic.
For example, I found a project that runs plex media server encoding jobs as Kubernetes pods: https://github.com/munnerz/kube-plex
When you’re not encoding anything, you’re not running much compute.
I think I’ve heard of game servers that wait for players to attempt to connect before starting the instance. If all you’re doing is playing a multiplayer game with friends that instance is going to be off 20+ hours a day.
Still, I haven’t done any napkin math on what applications represent cost savings.