What is a contract?
When can a contract be ended?
What are reasonable costs?
Delays in delivery and non-supply
Contracts with minors
Unfair contract terms
Loss or damage to consumer’s property
Misleading or deceptive conduct
What is a contract? 
A contract is a legally binding agreement between two or more people. Contracts can be oral or written. However, even for relatively straightforward arrangements, it’s a good idea to have a written contract, as it minimises misunderstandings and leads to fewer disputes. With an oral contract, it may be difficult to prove exactly what was agreed to, or even if a contract existed.
In some industries, written contracts are compulsory. For example, in the home building industry, a written contract is required between a builder and a customer for any job worth more than $5,000 (inclusive of GST).
A contract has three elements:
  1. an offer – eg. this may be made when you decide to buy something and offer to pay a price. You may also offer to give something or do something in return
  2. an acceptance – eg. this may be done by the seller agreeing to supply the goods or services. The acceptance may be in words or an action (eg. if you signed a written agreement accepting the terms and conditions)
  3. consideration – this is the value (usually money) that is given in return for the goods or services offered to be supplied or acquired. It may also be the promise to pay at a later date after certain events occur or procedures are followed.
Consumers should be aware however, that payment of a deposit and/or signing any documents may well mean they have entered into a contract and are bound by the terms and conditions of that contract. 
Be aware that despite what is in the contract, there may be terms and conditions outside the agreement that the law imposes. For example, it's no use having a clause saying 'no refunds' when the law actually gives people a non-excludable...