Just to get started, all you need is a 2GB Ubuntu instance that is $10/mo or pick rsync.net with zfs capability which gives you 1TB for $25/mo.

If you want easy fast backup, even hobbyist shouldn't overlook zfs.

Besides, Borg doesn't work with any cloud providers but only can go against ssh servers. You can also use Hetzner than rsync.net for this.