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." David is of the view that he is entitled to the gift card with $30 credit on it. Since his dealing with the bookshop, David has tried to take his mind off the missed gift card and decided he needed to purchase a laptop for his University studies. Peter, a marketing student at WSU (who happens to be David's friend), has a Macbook Air which he has advertised on a private sales website, www.lemontree.com.au, for $2000. David saw the advertisement and sends an email to Peter and asked, "Is this laptop the latest model and does it have a good camera and quality speakers? I can pay you $1500." Peter replied via email, "Yes it is the Macbook XVIII, the latest premium range and it does have the features you enquired about. I have a lot of interest in the laptop.I am keen to sell quickly.My final price is $1900." David replies via email stating, "We've got a deal, but I will need to pay you in weekly instalments." Peter then states, "If I don't hear from you in 3 days' time, I assume that you are keen to purchase the laptop. I will need a lump sum amount to be paid I'm afraid." The next day David finds out that Peter sold the laptop to his friend Luke for $1500.00. He approaches Peter and says, "We had a deal, you owe me the laptop".
Advise David whether there are any contracts in existence in the above scenarios and if he has any rights under them.