Depends what you mean by that?
I could port forward to a server in my home and host for free, but that adds complexity and raises security issues, also reliability is a factor.
I could host on any public service, you can do that in a small way for free, but high usage requires fiat.
I could setup my own server in the cloud, but that requires fiat.
Mostly, if I'm going to pay for a public service, I'd rather do this on a NOSTR focused server and support the developer.
Install minio or blossombat home.
Problem solved
You can even offer a upload service
But you rather participate in centralization on nostr
I have 3 nodes at home which run various NOSTR services, I didn't list them here as I am only discussing my spending choices.
I am not trying to reduce my spend, I am trying to increase my support for developers.