I was researching something earlier and ran across an interesting idea for backing up your QuickBooks file.
Set your QuickBooks to automatically backup every time you close it (make sure you’re using the data verification!!) and set it to save in your DropBox folder!
I don’t know why I didn’t think of this sooner, as I use DropBox and LOVE it! The free version comes with 2 MB of storage space, but honestly, I’m not anywhere even close to that right now (only using about 6% of my space).