1) Amazon has several 12TB HDDs for under $100 right now. One might be able to do better by shopping around to some other online retailers too.
2) Yes, but they are generally good for individual-level use for 5-10 or more years. I've got a few that are towards 20 years old and will fire right up and are usable. If we want to be very pessimistic, let's give the purchase ONLY 5 years before we have to replace it. My guess is 12TB HDD will be down at about the iCloud 12TB
monthly price in 5 years, so spend one
month of iCloud rent to own the same capacity for the next 5-10 or more
years.
One hard disk in a closet is certainly not the same as managed cloud storage. If someone wants to really pinch pennies, they should buy 2 of those 12TB drives, make both Time Machine drives and store one of them offsite. Regularly rotate offsite with onsite so offsite disc is always reasonably up to date. Total budget for this might go towards about 4 months of renting 12TB in iCloud. This should work well for 5-10 or more years instead of only 4 months.
But if one wants cloud, buy a nice NAS like a Synology for maybe about 10-12 months of iCloud rent, use the wizard to create your own Cloud of any size for $0/month subscription and enjoy a free cloud for the next 5-10 or more years... as opposed to paying $60/month for those 5-10 years (math definitely worth "what if"ing out to rationalize the option).
I've been doing exactly that for the last 10 years. It took about 30 minutes to set up with the Synology wizard all those years ago. I've had ONE drive in the set conk in those 10 years- which doesn't interrupt use (just needs to be replaced)- and replaced it with a bigger one to expand the storage pool. $0/month subscription cost and the Synology can also do a bunch of other things for me too... like a
network based Time Machine backup for all Macs in the house, a
whole house DVR for all AppleTVs in the house, etc.
BEST (general) OPTION: Synology or similar NAS for $0/month cloud + TWO 12TB or larger drives set up as Time Machine drives, with one always stored offsite. Regularly rotate offsite one with onsite one so a complete backup offsite is pretty fresh. I store my offsite in a safe deposit box at my bank for $35/yr but could easily store it in a variety of free places if I preferred (friends place, family, work, gym locker, etc).
The extra two HDDs protect against fire/flood/theft risk at home, losing both Mac + Synology unit at the
same time.
Again, at $60/month even against this best option, it doesn't take very long for the total cost of rent to exceed the total cost of owning... and afterwards the owner keeps enjoying their cloud plus very secure backup system while the renter just keeps paying & paying & paying. Do the math for 5 years, 7 years, 10 years and the difference is several new iPhones and/or Macs.