More importantly, if you find something free, expect it to be from a very sketchy company. You should be paying for something like this, and you should go through a company that you TRUST.
Chiming in to repeat the same as before commenters:
Nextcloud is only an option if you are trying to selfhost something that google and apple are giving you for free in exchange for your data. Is it secure there? somewhat. Is it private? Well, not so much but they’re not breaking any laws as far as we know.
Now there‘s nextcloud. It is only as private as you make it and only as secure as you make it. If you host it on a sketchy server out in the open, you can bet you will be compromised (your data lands in someone elses hand) or you will lose it alltogether.
So, think of nextcloud as the privacy twin of icloud and google cloud for the tech literate. If you‘re not ready to self host it, pay for the host or the electricity or don‘t know how to harden it against attacks, please use a big tech option.
Hetzner is a great VPS provider that can manage nextcloud for you, check this out: https://www.hetzner.com/storage/storage-share I think it's a great upgrade on privacy with the administration and security being all covered by profesionals ;)
I recommend setting up a home server using any old PC or laptop you have. Not having a static public IP may not be an issue, but if you are behind CGNAT, and cannot forward ports, you can route your data through a free provider like Oracle or Google. Those free servers are very weak but will be good enough to just pass through the data. This way even if they randomly decide to shut down and delete your instance, your data stays intact. I also recommend using SSL/TLS pass through, instead of termination, for better privacy.
Hosting yourself is the only "free" thing you're going to get. You may get a 1/2 core CPU on aws somewhere, but you're going to exceed that. Even then storage is not free, and if you're using someone else you're renting it from them, so yeah it's going to cost money.
quite a secret that I'm giving out, but for like 3€/month you can use the 1blu webserver to not only get 40GBs of nextcloud storage, but also 2 domains, unlimited emails and of course webhosting
Only problem is the company themselves, they seem quite sketchy and i don't really trust them to handle my data on their servers safely
But on the other side their the cheapest place i know so whatever
If you can get it to run on arm64, and you can manage to provision an instance (they are in seemingly perpetually limited supply), evil Oracle actually has a pretty generous always free tier Ampere offering. You can have up to 4c/24GB instance for free, sliced and diced as you see fit (4 1c instances, for example). You only get 200GB of block storage, though, so you'd have to either pony up for that or use object storage (not sure if nextcloud can use S3-like API object storage).
The things you'd normally use Nextcloud for is not the sort of thing that I would ever trust to be hosted for free, there's bound to be a catch (whether that is the service just disappearing over night, your data being collected and used for some nefarious purpose, etc).
It's definitely worth either self hosting, or if you're not able to, paying for some VPS to host it on.
Because if it's just cheap/free storage, this is not the answer.
You're typically using nextcloud because you want control over your data. And control costs something. Either selfhosting (which most of us do) or on someone else's server.
Otherwise, go to Google or Microsoft or something.
Imo shared seedboxes with a large app selection that includes nextcloud are the best bang for the buck storage wise, even if you never plan to use it for seeding.
So, I pay a company for a website hosting with PHP and they have an autoinstaller of Nextcloud.
After installing it, you can go into settings, add a S3 bucket you can get with free Storj account.