Here in the USA most companies post a disclaimer on print and internet "ads" which clearly indicates they are not responsible for errors or 'typos'. Once an order is accepted, and a credit card is charged, that may be another story. I am not an attorney, so take this as my personal viewpoint only, and not legal advice.... Seems to me that, prior to charging the credit card and shipping out the product, it is simply a matter that either part can change their mind and cancel their order. Lawyers in the audience? correct me if I am wrong here.
The website's disclaimers will generally become part of the contract for sale and will still apply even if the purchaser has paid (accepted the contract terms and performed, in the legal speak). The terms might state, for instance, that the website's only obligation in the case of typos is to return the money paid.