An offer, with minor exceptions discussed below, is essentially a promise to do or refrain from doing some specified thing in the future. A promise has been defined as “a manifestation of intent to act or refrain from acting in a specified way, so made as to justify a promise in understanding that a commitment has been made.” It also has been defined as an assurance that a thing will or will not be done.
While the First Restatement included the word “promise” in its definition of offer, the Second Restatement does not. It defines an offer as “a manifestation of willingness to enter into a bargain so made as to justify another person in understanding that his assent to that bargain is invited and will conclude it.” Apparently, the reason why the word “promise” is not used in the Restatement Second’s definition of “offer” is that it intends to include in the word “offer” an executed sale or barter where no promise is made by the offeror or the offeree. For example, assume that A says to B, “my car which is in your possession is yours if you pay me $1000.” If B pays the $1000 there is an acceptance of the offer and a complete exchange without any promise being made. This situation should be compared with what is described below as a “reverse unilateral contract” another situation where the offeror does not make a promise. However, the offeree does promise.”
One analyst, although not noting the omission of the word “promise” in the Second Restatement concludes that the omission of the word in the Uniform Commercial Code is of great significance. He emphasizes that the Code instead stresses the word “agreement” and defines it as “the bargain of the parties in fact as found in their language or by implication from other circumstances including course of dealing or usage of trade or course of performance as provided in this Act * * *” It is difficult to see how this definition undermines the importance of promise in determining the existence of an offer.”
Once it is decided that a party has made an offer it follows that the offer invites an acceptance. In other words, an offer empowers the offeree to create a contract by his acceptance. Despite the extended discussion above the typical offer is promissory in character. The acceptance of a promissory offer transforms the offeror’s promise into a contract « unless there is some other impediment to the existence of a contract.