With regards to the case of Susan, whether she may successfully sue Elizabeth or not, there is no precise answer. It depends if the contract is effective or not. For a contract to be valid, there are four key elements, which are "offer", "acceptance", "consideration" and "legal intention". Without any one of them, there is no contract at all and the agreement cannot be legally enforceable --- and this is the main area where this case concentrates on.
In this case, Elizabeth placed an advert to sell her bike, which was an invitation to treat. …
