Canadian contract law has its foundation in the English legal tradition of the 19th and early 20th century. It remains largely rooted in the old English common law and equity. Individual provinces have codified many of the principles in a Sale of Goods Act, which was also modeled on early English versions. Quebec, being a civil law jurisdiction, does not have contract law, but rather has its own law of obligations that is codified in the Quebec Civil Code.
In following with the common law tradition, a contract requires offer, acceptance, and consideration. The parties themselves must be capable of contracting and must have the intention to create legal relations.
An offer must be some indication of the offeror to the offeree that he is prepared to form a binding legal agreement. Intention is measured objectively. Commercial deals are presumed to be of a legal nature while an agreement made between family members or in a social engagement is presumed not to be of a legal nature.
An offer must also be distinguished from an invitation to treat, which is where one party invites another party to consider a deal.
Advertisements are also considered invitations. Exceptions are made in circumstances where a unilateral contract for performance is offered or where the advertisement is sufficiently serious about its promise such as in the famous Carlill v. Carbolic Smoke Ball Co.. In the similar case of Goldthorpe v. Logan, [1943] 2 DLR 519 (Ont CA) an "absolute and unqualified" guarantee to safely remove all hair by electrolysis, was found to be an offer as the plaintiff paid for the treatment on the basis of the offer.
The display of goods in store is typically an invitation. The quotation of the lowest price is also considered an invitation. However, in some circumstances a quotation will be an offer. In Canadian Dyers Association Ltd. v. Burton, [1920] 47 OLR 259 (HC), a quotation followed by the statement "if it were anyone else I would ask for more" was considered an offer.