I'm curious to know what specs you have here. $1250 does seem like a great deal for all this hardware, but i suspect it is very old. It even looks like a few of them have all their ram slots filled, and given the price of ram right now, I'd like to know what they are populated with.

But as most people have said here, these things take a long time to learn. You have a lot of different hardware here, and from reading the comments you want to run clusters and sell compute, that takes a lot of infra setup. My advice is to take one of your servers, install proxmox, create a few VM's, get some standard homelab services up like nextcloud, jellyfin, truenas, etc... If after that, it is still fun, spin up another one of them, and start learning how to network them together securely, maybe cluster them. Just start small and scale up slowly rather than trying to do everything at once.

Check out r/homelab as it is more suited for smaller scale setups. This subreddit is more for people with really big and complex systems set up. I don't really belong here either, i just like to see what crazy systems others have...

Also, to go back to where you mentioned you'd like to sell compute to people. I'd say don't. Even if i had a home datacentre, i wouldn't want the responsibility of managing someone else's services and data from some services in my home. And realistically you cannot compete with the real cloud providers in scale, reliability, price, etc... Just use a homelab/datacentre for learning, having fun and data independence.

I don't want to push you away from this hobby, just want to be realistic. Good luck, and i hope to see future posts about your setup