Whilst perusing a catalogue, David sees an advertisement for sale of second-hand books at the University co-op bookshop as follows "Up to 50% off on all finance textbooks. Hurry! While stocks last. If a customer spends at least $50 in store, they are entitled to a gift card with $30 credit on it which can be used anytime over the next few months." David decides to visit the bookshop that afternoon and when there, observes a promotional table which had the sign "All Finance books $10.00". David thought it was quite a bargain, picked up 3 books and went to the cash register handing the cashier $30.00. The cashier told David that the books were wrongly priced and that each of them should in fact be $20.00. David informs the cashier that the only reason he came to the store was because he saw the catalogue advertising a discount promotion and insists he be sold the books at $10 each. David then enquired whether he could at least get the gift card with $30 credit on it if he spends more than $50 in store, to which the cashier replied, "No sir, that advertisement was not meant to be taken seriously." Advise David whether there are any contracts in existence and if he has any rights under them.

You are advised to discuss the elements of a Contract generically in a separate introductory paragraph Then, attempt a mini-IRAC answer for the scenario, elaborating only on the specific relevant rules and principles under each of the elements, as supported by relevant case-law. This is to avoid repetitive discussion of principles which might inflate your word count.