An offer is a statement by the offeror of what he will give in return for some promise or act of the offeree. As the offeror's statement necessarily looks to the future, it must always be promissory in terms. It is sometimes assumed that an offer is something different in its nature from a promise and from a contract, but this is a mistake. An offer is always a conditional promise and it may be a contract.9 An option for which consideration is given, or which is under seal (in jurisdictions where seals still retain their efficacy) is a contract but it is also an offer which, when accepted, will create another contract or a sale.10
If no consideration is given for an option, it is merely a revocable offer.11
An offer is to be known from other conditional promises only because the performance of the condition in an offer is requested as the exchange or return for the promise in the offer,12 thereby giving the offeree a power, by complying with the request, to turn the promise in the offer into a contract or sale.13 The offer may be for the formation either of a bilateral contract or of a unilateral contract. If the former, the offeror's statement is not only promissory in terms when made, but will remain a promise after the formation of a contract by acceptance. If the offer contemplates the formation of a unilateral contract, it may be that the offeror proposes to exchange his own promise for an act of the offeree or, conceivably, that the offeror proposes to exchange an act on his part in exchange for a promise which he requests from the offeree. In fact, an offer contemplating a unilateral contract is almost invariably of the former sort; that is, the offeror is the party who becomes bound as promisor when the contract is formed by acceptance. Even when the offeror in terms offers an act of his own in exchange for a promise to be made by the offeree, the words of the offer are necessarily promissory, for the offeror must, in the nature of the case, announce that he will do a certain act in the future, in return for a promise to be made to him. Indeed an offer which requests from the offeree a promise will, when accepted, always ripen into a bilateral rather than a unilateral contract, except in one narrow class of cases; namely, where the very giving of the promise by the offeree also has the effect of completing the act promised by the offeror. The only instance of this sort that can be supposed arises where the offeror offers (that is, promises) to transfer title to personal property on receiving a specified promise from the offeree. As title to most kinds of personal property will pass by the mere assent of parties, it follows that when the offeree makes the promise requested the requisite assent is had and he at once becomes the owner of the property offered. The offer though in terms a promise when made, thus becomes fully executed by the transfer of title at the instant the contract is completed by the promise of the offeree. A unilateral contract is thus formed in which the offeror has performed the act (transferring the ownership of goods) which is the consideration for the acceptor's promise.14
8The requisite certainty of offers and of promises contained in them are considered in infra, Sec.Sec. 37-49.
9Graves v. Smedes' Adm., 7 Dans, 344.
10 Bee infra, $ 61.
11 Smith v. Bangham, 156 Cal. 359,
104 Pac. 689, 28 L. R. A. (N. S.) 522; Walter G. Recee Co. v. House, 162 Cal. 740, 124 Pac. 442.
12 As to when stating a condition in the promise involves such a request, see infra, Sec. 112.
13Hohfeld, 23 Yale L. J. 49; Cor-bin, 26 id. 181.
14 See Emerson v. Stevens Grocer Co., 95 Aril. 421, 130 S. W. 541, 544, 106
Since an offer must be a promise a mere expression of intention or general willingness to do something on the happening of a particular event or in return for something to be received does not amount to an offer.15 Therefore an ordinance or resolution of a municipal corporation 16 or a vote of a private corporation,17 does not of itself amount to an offer, though it may be so communicated by the corporation to another as then to become an offer.18