It couldn't be easier or cheaper to implement your backup plan today, as you can purchase a full 1.2 terabyte hard drive (1,200 gigabytes) today for less than $330.
I already own a terabyte array as a storage backup on my home computer. And that drive will suffice for backing up just about anyone's files, unless you work on some serious video editing or store your videos on your home computer.
The links below give you the various options for either an internal or conveninen external drive. You simply can't use the drives are too expensive for an excuse anymore.