The Australian dollar is used, made up of 100 cents. Our smallest coin is 5c and totals are rounded up or down to the nearest 5c value. Other silver coloured coins are the 10, 20 and 50 cent coins, with the $1 and the smaller $2 coins being gold coloured.
Our notes are different sizes and colours with many security features, such as watermarks and see through strips. $5 is purple, $10 is blue, $20 is red, $50 is gold and $100 is green.
Generally Euros, Pounds and US dollars are worth more than the Australian dollar. So prices will seem cheaper if you are used to those currencies.
In addition, all prices include taxes, so the price you see is the price you pay.
Finally. tipping is generally not expected, with some exceptions:
Credit and debit cards are generally accepted, but be aware of exchange rates and fees. There are often higher fees for cards other than Visa and Mastercard and often only these 2 are accepted.
Some places are card only and others want cash, so you should have both. Often groups in restaurants get a single bill and a single payment is expected, not 10 or more credit card payments.