The good ones... Are not cheap (if someone knows a cheap option though, I'd be happy to add it to my own repertoire!)
For me, I backup with:
- A second NAS
- a clone to a NAS at two other homes (family), which also sync to mine
- Encrypted backups to generic cloud storage
Edited to add:
You dont need to backup everything.
What is being backed up by me at all the locations above:
- Content I can't replace (home photos, movies, etc)
- Configs for services
- Personal documents and other such data.
- etc
Aside from the home movies, its not a huge amount of data. Lots of VHS conversions of graduations, Christmases, etc of long past.
Locally I back up more to the second NAS including:
- Content I can replace but this is faster
- Full backups of VMs
- LXC snapshots
- etc
So while I have a huge amount of storage at home, what's needed elsewhere is not anywhere near as much.