It depends on the generation. Older tapes and drives are a lot cheaper, especially second hand but hold less (tapes aren’t meant to be overwritten a lot though so typically you want unused. New old stock or new).

Most homelabbers use LTO-6 or 5, and you can also upgrade your drive and still read your old tapes (except for the newest generations iirc)

I haven’t looked at a process comparison for years, so I’m going off pre AI numbers. It was cheaper then spinning rust back then for $/TB (for my setup it was cheaper than rust by a massive margin since it have a quarter petabyte of storage. Amortizing a tape drive over that many tapes gets cheap quickly), but maybe its different now?