An offer is a statement of terms under which the offeror agrees to be bound. It is a promise that one party makes in exchange for another partys performance. An offer can be expressed in many different ways, from a short and simple oral statement to a long and detailed written statement. The offeror proposes the terms of the agreement or "makes an offer," while the offeree receives the offer and either accepts or rejects it. For an offer to be valid, it must contain specific elements, including:

• Specificity: The terms of the offer must be clear and definite so that the person receiving the offer understands what they are agreeing to.

• Legality: The offer must be legal and something the offeror can do or refrain from doing.

• Specific offeree: The offeror must give the offer to someone.

• Ability to accept: Some types of offers have deadlines or expire by the terms of the offer.

An offer can be the basis of a binding contract only if it contains the key terms of the contract. For example, in some jurisdictions, a minimum requirement for sale of goods contracts is the following four terms: delivery date, price, terms of payment that includes the date of payment, and a detailed description of the item on offer including a fair description of the condition or type of service. If the minimum requirements are not met, an offer of sale is not classified by the courts as a legal offer but is instead seen as an advertisement.