Secon hand goods

Pawnbrokers and second-hand dealers
Pawnbrokers and second-hand dealers are required to hold licences issued by the relevant fair trading authority in your state.
The rules vary between the states, but dealers must be licensed to sell certain specified items such as jewellery with gemstones or precious metals, sporting, musical and photographic equipment, tools, car accessories and mobile phones.
There are strict rules about how they may go about lending money or accepting goods for sale or as security, as well as about the types of goods they must be licensed to sell.
Second-hand dealers and pawnbrokers are bound by the federal Trade Practices Act and state fair trading laws.
Buying at auction
An auctioneer acts as an agent for the vendor, the person offering the item for sale. The vendor is often a private individual, and therefore not usually subject to state fair trading laws (fair trading laws do apply if the vendor is a business).
Goods at auction are mostly sold “as is”. In most cases, you’re expected to have inspected the goods in advance and are accepting them with any defects or faults.
Fair trading laws may apply if you purchase something at an auction and it turns out that the vendor didn’t own it in the first place (perhaps the item was stolen or encumbered by an outstanding debt), and when there has been a misdesription of the goods. In such a situation, you’d seek redress from the auctioneer. In other situations, disputes arising from auctions are civil matters that need to be resolved through your local court.
In South Australia, goods bought at auction don’t have any implied or statutory warranties (even if the vendor is a business), so you’re accepting all responsibility for the quality of the goods.