I kinda overdid it with a tape library (40 tapes capacity, LTO-9), but I'm using it for my company's AI model backups. _That_ setup was about $12k.

I had a smaller setup before, with a simple external LTO-5 drive. Used drives are now are about $300, and you can probably find them cheaper. And LTO-5 is the minimum realistic version, it's the first one that supports LTFS and it has reasonable tape capacity.