To Amazon Cloud Drive

You can't beat the flexibility and price of ACD. Currently it's $60/year for unlimited storage (and only $5 for a  year at the last black-friday sale). It's a storage solution though, not a backup solution. To get the latter you need to use it as a back-end for backup software and to make it available, you need the acd_cli utility

Once you've got it configured, you can use it as a back-end for duplicity (as long as you have 7.07 or higher) or mount it though FUSE and use obnam