(Alternative below) Buy 5 - 7 years old computer with decent specs (i5 i7, 16 gigs ram, don’t care about hard drives but prefer ones with ssd) for about 60 - 100 bucks. Buy 250 gigz+ ssd (if it’s not included) and any desired number and sizes of nas grade drives (this is where you don’t want to save money). Don’t forget UPS! Install TrueNAS. Profit… Ok not profit but enjoy. For movies definitely jellyfin (keep your distance from plex really). Audiobookshelf for audiobooks but also ebooks! Amazing software that one.

Alt. Buy raspberry pi, two usb hard drives, install open media vault and same apps as above. It’s not as polished as true nas but its cheap and it lets you dip your feet in homelabbing first, in two to three years you will gain experience and vision to do your dream homelab (or at last try 😀) if the pi is not enough.