Cheap 16GB USB 2.0 drive for $5. Not much more to say!
Seemingly limited online to 5 per customer; no limit in-store. Preferably click-and-collect to save on shipping.
Colours:
Protip for backups from Merlin Mann:
Make and Update Multiple "Go-Sticks". Buy a bunch of good 4GB+ USB sticks and use them to hold 256-bit-encrypted sparsebundles of your "Holy Shit!" files. Keychains, 1Password files, bank account numbers, insurance records, etc. Anything you need to either start recovering from a catastrophe or go on the lam. Make multiples, schedule update reminders, swap them out in known locations, and, if you have the skillz, maybe set up an Automator script that automatically updates the contents of each drive whenever you plug the little buggers in.
https://www.computeralliance.com.au/parts?id=10316