Credit to these post and comments.
Prices in the title are promo prices valid for the first 3 months for new customers. If you choose to continue after the first 3 months, HiFi plan is ARS 99/month or ~AUD 1.33/month. HiFi Plus plan is ARS 145 or ~AUD 2/month assuming you pay with cards with no foreign exchange fees.
Family plan (Argentina) is about AUD 2 for HiFi and AUD 3 for HiFi Plus per month after the first 3-month promo period.
I paid for HiFi Plus with my 28 Degrees card and got charged AUD 0.27 for the 1st month. There was no Paypal option.
Very straightforward process:
Use a VPN to connect to an Argentinian server (required only for registration).
Open an incognito browser window.
Sign up via the main link in this post
Pay with a card that has no foreign exchange fees.
Enjoy the full benefits of Tidal HiFi or HiFi Plus.
Credit to xiaoli:
HiFi Quality Sound
Up to 1411 kbps
Innovative Audio Formats
Up to 9216 kbps
Master Quality audio, Dolby Atmos, Sony 360 Reality Audio, and HiFi