I've just received my first order which included postcards, and I am very happy with them. I had some "art" ones made up that I can use for birthday/greeting cards, and some made up for one of my hobbies - www.bookcrossing.com - that I can include in books I release or pass on to friends. The possibilities of what you can do with your postcards are pretty broad - why not a Christmas or New Years card? A generic party invite that you can have printed with "Who What When Where Why" on the back and handwrite the details as the occasions approach? I've got a million ideas!
Mine arrived from Belgium, and I spent around $20 on postage for a large number of freebies - people may prefer not to order from overseas so I thought I'd give a heads up.
The link will take you to a page from which you choose the Australian site - I am not sure, but I thought a deep link might not enable you to get the BuckScoop cash back?