In general rule, an advertisement is an invitation to treat as it is an expression of willingness to receive offers as the starting point of negotiations (Partridge v. Crittenden ). Therefore, the notices that displayed in the book shop stating a special promotion can be considered as an invitation to treat. When Mary took a copy of Anson’s Law of contract from the shelf and went to the counter for payment. The action of Mary that when she saw the notices then took a book from the shelf to counter for payment is making offer to the shop (Pharmaceutical Society of Great Britain v. Boots Cash Chemists Ltd). This means that the offer to purchase a book is made at the cashier counter by Mary. The book shop is then free to accept the offer or reject it and thereby the cashier can reject that offer if desired.
To conclude this case, the notices displayed in the shop is a statement that made by the book shop inviting offers which the book shop is then free to accept or reject it. Mary’s offer is rejected by the cashier of the book shop. Therefore, Mary cannot buy a law book at the discounted price in this situation.