Arq is another great alternative, which combined with Amazon Unlimited Cloud Storage, gives you the same benefits as Tarsnap for orders of magnitude less.
And while I've got your attention, 1) are Arq backups encrypted and 2) can it back up via SSH to my own storage somewhere - like a cheap VPS with lots of disk space?
2) Yes. Although if you're after cheap space, Hetzner's storage boxes are the cheapest $/GB I've seen (https://www.hetzner.de/hosting/produktmatrix/storagebox-prod...), with Backblaze B2 close behind.