You can host Nextcloud at your home using something like NextcloudPi+DDNS (https://nextcloudpi.com) or HomeDrive (https://homedrive.io, which has ngrok-ish end-to-end tunnels integrated), and the monthly cost would be almost $0. :)
It's cheap if you already own the hardware. Even $300 could be 50 months (4 year) of a remote server at the prices suggested by some of the posts in this page.
Furthermore self hosting a backup server at home doesn't protect against burglars and fires. You'll probably lose both your data and their backup.
That's why I prefer a local backup plus a remote one (a combination of git repositories and file storage. )
I recently set up Nginx on a DO droplet as a reverse proxy to my home server over Wireguard. It's not $0 but it doesn't directly expose my home IP. And I have an authoritative resolver on the LAN so local clients go directly to the private address.
HomeDrive ( https://www.homedrive.io ) is plumbing exactly this! We are currently only hosting Nextcloud, but we plan to support more apps and custom dockers. It is as easy as plugging the box into the home router.
There are still many features to implement, but we are working towards "easy self-hosting at home", and looking for early adopters.
HomeDrive features plug-and-use, with no system maintenance required. We target not only developers/hackers, but also end-users who would like to have a small server at home, to host their own data and services for their digital lives. As a result, HomeDrive also maintains the OS to be reliable and secure, which is why we picked the hardware. We are investigating supporting more hardware, such as raspberry pi's.
KubeSail feels like a more accessible k8s+docker apps to me. I am not sure what security model KubeSail is assuming for the operating systems it is running on (or does it assume the OS is out of the scope?). Also KubeSail seems to target mostly developers/hackers.
It also terminates TLS at the box, and has no recurring charges.