I just grab them off ebay. SAS drives are almost exclusively used in enterprise servers, so there’s fuck all demand for them on the used market. Buy a cheap PCIe SAS controller card and you’re good to go.
I use Unraid which doesn’t care at all about what types of drives you use, so you can mix and match into one huge array. I have 8x SAS and 2x SATA drives in one array.
“I can’t install an app because a dependency depends on another dependency that I already have installed but in ever so slightly the wrong way, but I have another app installed which depends on this dependency being installed the way it is now, so I’ll have to compile the app from source instead and tweak the config file to work with my version of this dependency, but I also can’t compile the app because of the dev environment dependencies.”