Consideration

• Some contracts do not specifically state the price that is to be paid for the work or services raising questions about what the consideration is;
• A promise to do something illegal may on its face be consideration but it is not;
• Where one party has an unfettered discretion whether or not to perform the contract may not have consideration, and could be illusory.
• A debtor tells a creditor that it will pay part of the debt owed which may in fact not be consideration subject to some exceptions.

In cases of this class it is necessary, in order that a contract may be established, that it should be made to appear that the statement or announcement which is relied on as a promise was really offered as consideration for the doing of the act, and that the act was really done in consideration of a potential promise inherent in the statement or announcement. Between the statement or announcement, which is put forward as an offer capable of acceptance by the doing of an act, and the act which is put forward as the executed consideration for the alleged promise, there must subsist, so to speak, the relation of a quid pro quo. One simple example will suffice to illustrate this. A, in Sydney, says to B in Melbourne: "I will pay you £1,000 on your arrival in Sydney". The next day B goes to Sydney. If these facts alone are proved, it is perfectly clear that no contract binding A to pay £1,000 to B is established. For all that appears there may be no relation whatever between A.'s statement and B's act. It is quite consistent with the facts proved that B intended to go to Sydney anyhow, and that A is merely announcing that, if and when B arrives in Sydney, he will make a gift to him. The necessary relation is not shown to exist between the announcement and the act. Proof of further facts, however, might suffice to establish a contract. For example, it might be proved that A, on the day before the £1,000 was mentioned, had told B that it was a matter of vital importance to him (A) that B should come to Sydney forthwith, and that B objected that to go to Sydney at the moment might involve him in financial loss. These further facts throw a different light on the statement on which B relies as an offer accepted by his going to Sydney. They are not necessarily conclusive but it is now possible to infer (a) that the statement that £1,000 would be paid to B on arrival in Sydney was intended as an offer of a promise, (b) that the promise was offered as the consideration for the doing of an act by B, and (c) that the doing of the act was at once the acceptance of an offer and the providing of an executed consideration for a promise. The necessary connection or relation between the announcement and the act is provided if the inference is drawn that A has requested B to go to Sydney. - Australian Woollen Mills Pty Ltd v The Commonwealth [1954] HCA 20