Comment by g-garron

I use a combination of Dropbox and S3.

I have my MacBook and a Linux server linked to my Dropbox account. So changes in my documents are synced to my Linux.

My Linux run three cron-jobs. One daily, one weekly and another monthly. The command is.

s3cmd sync --delete-removed ~/Dropbox/documents/ s3://backup-daily/

There are buckets for weekly and monthly too.

Note: the command is not exactly like that, check the man page.

That way I have backed up all my documents very cheap.