First know the product you are after. Do research on different brands, sizes, materials and descriptions.
Secondly know the value of the product you wish to buy
Thirdly check the condition, Is it used? Is it worn? Is it worth the price including postage?
Fourth, and most important will postage using the Australia post system suit you?
Finaly if you have done & checked all the above, then all you have to do is wait till your product you wish to purchase becomes available and then check the seller out for negative feedback.
If you are satisfied its all credible then bid with ease of mind.
Register with paypal for faster & safer payment and the seller will email you when they post your goods.
Wait for the postie to deliver your package, or get a box and pick it up yourself, I find this faster & less of WORRY!
Open your goods & examine them closely, if they are what you expected, give positive feedback, If not then contact the seller & discuss your disappointment maybe an agreemant can be reached, before you leave a negative feedback.
Enjoy your purchase, you snared a bargain!