Most of the ones on Amazon aren't trustworthy. Especially at high capacities. But apparently you can get up to 2TB now, at least in theory. I imagine the support for them is pretty limited though still.

https://americas.lexar.com/guide-to-microsd-card-sizes/

In the uk I can get 1TB for 95gbp from sandisk website.

So probably less than 100 usd in usa from a reputable seller.

I bought a large capacity unknown brand cheap SD card somewhat recently, it seemed real at first but after installing an OS on it and running a few minutes became bricked somehow. At least I got a refund.

I bought a 512 GB SanDisk one for $65 USD a few years ago. I don’t like Samsung software bloatware on their phones, but having 512 GB of storage for $65 feels pretty futuristic to me. I can’t believe more phone manufacturers don’t offer external SD card support… you’d think more consumers would demand it, given that the alternative is to pay a lot more, every time you get a new phone.

I’m basically able to keep like every photo I’ve taken for the last 10 years or so (though not at original resolution).

They're sold as 1TB for that price. But if you actually write that much, you'll find that only part of your data is there. The rest is garbled or zero.

There's tools to restore this (on windows/linux), and it'll show up as a smaller size when you run them. You can also use such tools to set any fake size you like