For local redundancy, use a RAID 1 or RAID 5 setup, either in one of your home systems, or you can buy a simple NAS solution like a Drobo, and set it up for mirroring to multiple drives. The NAS unit ($350-500) + 3-4 4TB HDD's (~$120/each), or $700-1000 which will last years.

To do offsite, in case of fire, you can clone backups onto another harddrive or every few weeks or months onto blurays and store them at a relatives, safety deposit box, or somewhere else you consider safe and accessible. Or you are willing, for offsite matters, go a cloud provided like Google, Box, DropBox, which will charge you $10-20/mo for a TB of storage on their servers, you can use that.

I personally, don't use much offsite storage, for most of my data. I make occasional Blu-Ray or thumbdrive clones of important files and keep them in my bedroom, and accessible if I have to run. And while traveling I'll bring a set of thumbdrives with me.