A terabyte is no longer $20, unfortunately.

There's an 18 TB refurb from serverpartdeals right now. Or there are a bunch of smaller new ones in the $20s on Amazon. The analysis doesn't really change even if you're looking at e.g. $30/TB. It's still hundreds or thousands of items for a year of subscription cost; more than you could reasonably watch. Even going full 8 TB SSDs at $150/TB is still thrift store cost per movie when you amortize it ($2.25 at 15GB, or $0.30 at 2GB).

Of course then as another comment here said, you're more likely to realize you don't actually want any of it. And then when you realize it's not worth pennies to store, you also realize it's not worth your time to watch.

It's $30. It used to be $10, now it's $30. It's tripled in price but it's still cheap enough for pirated movies. If that's still too much, get the 1080p version instead.

This is about $/TB on bigger drives. If you only want a 1TB drive it'll be more like $50.

Don't get an SSD, far too expensive.