If you "back up and forget" there is a good chance you will not be able to restore the tapes when the time comes.

At least with drives you can run regular health checks a corruption scans. Tape is good for large scale but you must have automation that keeps checking the tapes.

Tape drives are generally SAS so you will need a controller card

I've got a HP StorageWorks Ultrium 3000 drive (It's LTO-5 format) connected to one (LSI SAS SAS9300-4i), in my NAS/file server (HP Z420 workstation chassis). Don't go lower than LTO-5 as you will want LTFS support.

About £150 all in for the card and drive (including SFF-8643 to SFF-8482 cables etc..) on EBay

Tapes are 1.5TB uncompressed, and about £10/each on Ebay, you'll also want to pick up a cleaning cartridge.

I use this and RDX (1TB cartridges are 2-4 times the price, but drives are a lot cheaper, and SATA/USB3, and you can use them like a disk) for offline backup of stuff at home.

You can buy a tabletop LTO tape drive, a SAS HBA card and an appropriate cable and you can use them with any desktop computer with a free big enough PCIe slot.

The problem is that while the tapes are at least 3 times cheaper than HDDs, and you have other additional advantages, e.g. much higher sequential reading/writing speed and much longer storage lifetime of the tape, the tape drives are extremely expensive, at a few thousand $, usually above $3k.

You can find tape drives for obsolete standards at a lower price, but that is not recommended, because in the future you may have a big tape collection and after your drive dies you will no longer find any other compatible drive.

Because the tapes are cheap, there will be a threshold in the amount of data that you store where the huge initial cost of the tape drive will be covered by the savings from buying cheap tapes.

That threshold is currently at a few hundred TB of stored data.

I use an LTO tape drive and I have recovered its cost a long time ago, but I have more than 500 TB of data.

However, only a third of that is actual useful data, because I make 2 copies of each tape, which are stored in different locations. I am so paranoid because it is data that I intend to keep forever and I have destroyed all the other supports on which it was stored, e.g. the books that I have scanned, for lack of storage space. An important purpose of the digitization has been to reduce the need for storage space, besides reducing the access time.

I keep on my PC a database with the content of all tapes, i.e. with all the relevant metadata of all the files that are contained inside the archive files stored on the tapes.

When I need something, I search the database which will give me the location of the desired files as something like "tape 47 file 89" (where "file 89" is a big archive file, typically with a size of many tens of GB). I insert the appropriate tape in the drive and I have a script that will retrieve and expand the corresponding archive file. The access time to a file averages around 1 minute, but then the sequential copying speed is many times higher than with a HDD. Therefore, for something like retrieving a big movie, the tape may be faster overall than a HDD, despite its slow access time.

There are programs that simulate a file system over the tape, allowing you to use your standard file manager to copy or move files between a tape and your SSD. However I do not use such applications, because they reduce a lot the performance that can be achieved by the tape drive. I handle frequently large amounts of data, i.e. the archive files in which I store data on the tapes are typically around 50 GB, so the reduced performance would not be acceptable.