I have moved to another country and left my 1TB WD HDD back at home which I was using with Time Machine to backup my device. I've used this device for years so it has backups from my previous MacBook. I am going to be working at home occasionally and since the Air has no CD drive I have no way of making backups which I now need. What is the cheapest (but also suitable and working) device I can buy? I'm happy to buy second hand from eBay or the likes. My SSD on my MacBook Air is 120GB so I guess I should be looking at a 500GB drive at a minimum, right? Also, I should point out i'm in Australia so shipment to Australia is required.