Just jumped back on Duolingo to find they're doing 60% off Super Duolingo if you buy 12 months worth.
In NZ, that takes it down to $115.99 for the year, but I remembered in the past trying out lots of countries to see what the prices were since it was otherwise almost $300 per year.
During that exploration, the cheapest I found was Brazil, and their geo-pricing is very basic, simple set the VPN then refresh with no addresses etc, just a post code during CC entry, but that should be and can be your NZ Post Code.
Using a basic, free VPN like TunnelBear, set it to Brazil, refresh or open the page and you can pay $44NZD for a year which is simply applied to your account, regardless of where you use it.
If you're bored, feel free to try other countries, but Argentina gets hit with full US price. UK and EU are all more expensive. Russian rouble is apparently quite expensive (although I haven't tried it myself, nor Turkey as Tunnelbear supports neither).
As a bonus, it actually says I'll be charged another 143 real on Jan 2024. So it looks like it becomes a permanent price.
You could use web version and ad free.