Unfortunately, this kind of service isn' t free, and the cost can be a barrier. However, there is a cost-effective way to store your cloud backups: Usenet. With access to a Usenet news server, you can simply upload your backup there, and it will be stored redundantly in news servers all over the world. Best of all, this approach typically costs considerably less than a cloud backup service.
Obviously, this is not your typical method of cloud storage. Many may snicker or find it plain weird to tap into this vintage part of the Internet in such a modern way. But oddly enough, we have experience experimenting with this alternative offline storage when it comes to backing up a Linux system. And backing up your Linux system to usenet ultimately requires only a handful of steps. It's not only possible - it's scriptable, too.
I didn't know this was possible, but that's mostly because I never thought of it. Clever.