If an item in a retail store is mistakenly placed on a Sale table by a customer or staff then someone wants to buy that item is there a law that states that that item must be sold at the sale price?

I have had the same situation where i found an item on a sale table but when i checked, it was placed there in error. The law applies to an item that is priced as on sale or has a sign that specifics a sale. The item must be sold by law at the price indicated even if in error.