1.1 An expression of willingness to be bound on specific terms.
1.2 Must be certain.
1.3 Only the person or a member of the class to whom the offer has been made can accept it.
1.4 The offer must be open for acceptance at the time that acceptance is purported to occur.
Invitations to treat
1.5 Offers must be distinguished from invitations to treat.
(a) This is inviting someone to make an offer or commence negotiations.
(b) It cannot be accepted.
(c) Examples of invitations to treat:
(i) items displayed on shelves: Pharmaceutical Society of G.B. v Boots Cash Chemists.
(ii) items in shop windows: Fisher v Bell.
(iii) usually adverts in newspapers: Partridge v Crittenden.
Note however offers made to the whole world: Carlill v Carbolic Smoke Ball Co.
(iv) auction notices.
(vi) mail order catalogues