Sorry I haven't put a budget down. I live in Australia which hasn't been doing too well against the US dollar, plus there are import costs etc, so it makes comparisons with the US difficult. I was looking for a generally cheaper solution (~200-300 AUD max), hence why I was considering using an old laptop as a server and/or raspberry pi(s). So some suggestions like a NUC or iPad Pro are a bit our of my price range ATM. I do in fact have an iPad, but I cheaped out on storage as I didn't think I'd need more than 128GB, would have been useful in this situation.
I can get a plain RP4 (no case, power supply, etc.) for about $74, but I'm unsure if I need any additions on it for my needs, or if a plain board + power supply + software will do the trick.
For those asking, I have around 200 gigs of music.
I'm guessing suggestions for the mini PC's are for the server? If it's for local playback I'd prefer it to be headless + controlled by mobile devices. For people suggesting this, do you think I should use a pi as an endpoint? Or is there a way to use a mini pc locally and control in via mobile?
A raspberry pi4 running PiCcoreplayer (free) via usb out into your dac would give you a technically near perfect solution for $50 or so. Why spend any more ? There are other software packages you can try as well. Volumio, Moode, etc.
Would this play files locally, or would I have to stream them from a home server? And would a plain board do, or would I need additions?
Put Roon on the laptop and hide it in a cupboard.
Use RPi as a headless Roon endpoint
Control via phone / tablet app.
Thanks for the suggestion, but I'm looking more towards software that's either free or a single purchase, I already have too many subscription services in my life!