I use the excellent TheyWorkForYou site operated by MySociety to keep abreast of what my MP, John Hemming, does and says in the House. Today I got a notification that he had recived a petition regarding the purchase of a Citeron car by a constituent. The situation, as I understand it, is that the constituent had ordered a car from Citeron before 1st April but collected it after. On first April Citeron reduced the price of the car, the petitioner seems to feel that they should have refunded to him the difference between what he had paid and the new, lower price.
Whilst this appears to be very bad customer service by Citeron I suspect that the legal question here is when the contract between him and Citeron was formed as it is in that contract that the price will be set. Is the contract formed when the order is placed? When payment, or the initial part payment, is made? Or is it when the goods are picked up. I seem to recall that the normal milestone is when the payment, or initial part payment, is made, at that time a contract is formed. If he paid a deposit ahead of 1st April and based on the higher price then the constituent probably locked in that higher price then.
Consider the reverse situation, if the price had risen on the 1st of April. Would the constituent have claimed that he should pay the new higher price or, had Citeron tried to charge him the higher price, would he be claiming that as he'd ordered at the lower price and paid a deposit he should only pay the lower price?