What is an Octopus card? Well, it is a card that works like an ATM card I guess! Most people in HK uses them as it is a card that you can top up with money! You can also elect one as your main card and everytime your money reaches zero, it will automatically top up for you via your credit card (This only applies if you live in HK as you need to link it to a HK credit card)!
And the most useful thing is that it can be used in a lot of places, MTR stations, trams, buses, restaurants, Watsons, KFC etc...
So practical as it saves a lot of time as you just placed it on the terminal and it will just beep which means that the money has been deducted and you have paid for your purchase! No waiting around while the person in front of you scrambles around his/her wallet taking out money and change.
How I wish that Australia can be as advanced!
However, for a tourist like me? I can only top up with cash at "Add Value Machines" in MTR stations like the one below! But I still love the convenience of it. You have to pay an initial deposit of HKD50 to use the card but when you return it, you get your deposit back (Apparently, if you return it within the first three months, you only get HKD43 back though!). So, it's still good! Especially for a tourist like me as it takes longer figuring out the foreign notes and coins.