Don't disagree with your post, I've gone that route too, but I have had a couple RAIDs crash over the decades and dashing to a computer store and slapping drives from a dead box to a new one got me back up and running the quickest.
I can totally build a server with my spare parts lying around, but my system doesn't care when I have free time to tinker; assume it will fail at the worst possible time like the day you leave on vacation.
But yeah, if you're pinching pennies, build something fun and learn along the way. Frustration is the key to memory permanence. 😁