OFFERLaw of Contract
An offer is an expression of willingness to contract made with the intention that it shall become binding on the offeror as soon as it is accepted by the offeree.Definition of OfferOfferor the person who make the offerOfferee the person who takes the offer
Mode of OfferOffer may be made in writing or verbalOffer may be express or impliedSomething that is said to indicate that an offer is being madeSomething that is done, that though not expressly communicated, automatically indicate the act of offer.
An offer may be made to a particular individual or to a group of peopleIf the offer is made to a specific individual, only that person may accept the offerIf an offer is made to a group of people, then anyone from the group may accept the offer.
Transactions that are not Offer but Invitation to Treat
Invitation to TreatAn "invitation to treat is where a party is merely inviting offers, which he is then free to accept or reject. AuctionsAn auctioneer's call for bids is an invitation to treat, a request for offers. The bids made by persons at the auction are offers, which the auctioneer can accept or reject as he chooses. Similarly, the bidder may retract his bid before it is accepted.Payne v Cave (1789)
2)Display of GoodsThe display of goods with a price ticket attached in a shop window or on a supermarket shelf is not an offer to sell but an invitation for customers to make an offer to buy.
Fisher v Bell P.S.G.B. v Boots Chemists 
3) AdvertisementsAdvertisements of goods for sale are normally interpreted as invitations to treat.
Partridge v Crittenden 
However, advertisements may be construed as offers if they are unilateral, ie, open to all the world to accept (eg, offers for rewards).
Carlill v Carbolic Smoke Ball Co 
4) Mere Statement of PriceA statement of the minimum price at which a party may be willing to sell will not amount to an offer.
Harvey v Facey  Gibson v Manchester County Council 
5) TendersGoods advertised for sale by tender, is a request by the owner of the goods for offers to purchase them. The statement is not an offer, but an invitation to treat.
Harvela Investments v Royal Trust Co. of Canada  Blackpool Aero Club v Blackpool Borough Council 
Supply of InformationThe act of supplying information does not show intention to be bound by the reaction of the person receiving the information Harvey v Facey (1893) Bigg v Boyd Gibbins Ltd (1971)
Statement of IntentionA mere statement indicating a persons intention to do something is not an offer. Harris v Nickerson (1873)Transactions that are not Offer at all
For an offer to be effective, the offeree must have knowledge of the offer.
It is impossible to accept an offer which you have never heard of
Taylor v Laird (1856)Communication of Offer
Termination of the Offer1) AcceptanceOnce an offer has been accepted, a binding contract is made and the offer ends.
2) RejectionIf the offeree rejects the offer that is the end of it.
3)Counter OfferThe original offer is modifiedCounter offer rejects the original offer, rendering the latter no longer available for acceptance, unless if the offeror renews his offer.However, a request for information is not counter offerHyde v Wrench (1840)
4)Lapse of timeWhere an offer is stated to be open for a specific length of time, then the offer automatically terminates when that time limit expires. Where there is no express time limit, an offer is normally open only for a reasonable time.Ramsgate Victoria Hotel v Montefiore (1866)
5)Failure of a ConditionAn offer may be made subject to conditions. Such a condition may be stated expressly by the offeror or implied by the courts from the circumstances. If the condition is not satisfied the offer is not capable of being accepted. Financings Ltd v Stimson  3 All ER 386.
7) DeathThe offeree cannot accept an offer after notice of the offeror's death. Unless if the offeree does not know of the offeror's death and he accepts it in bona fideBradbury v Morgan (1862) 1 H&C 249
8) RevocationThe offer may be revoked by the offeror at any time until it is accepted. Revocation of the offer must be communicated to the offeree(s). Unless and until the revocation is so communicated, it is ineffective Byrne v Van Tienhoven (1880)The revocation need not be communicated by the offeror personally, it is sufficient if it is done through a reliable third party Dickinson v Dodds (1876)Where an offer is made to the whole world, the offeror must take all reasonable steps to revoke his offer Shuey v United States  92 US 73.Once the offeree has commenced performance of a unilateral offer, the offeror may not revoke the offer.
Errington v Errington  Daulia v Four Millbank Nominees