Not if it was accidental.
When a retailer displays a product for sale, legally it is giving you 'an invitation to treat', which means it is inviting you to make an offer to buy. The retailer can refuse that offer if it decides that it doesn't want to sell you the goods. To have a legally-binding contract the retailer must have accepted your offer to buy. So your rights depend on where in the sale process you are.
If you order an item on the internet, you don't have a legally-binding contract until the retailer has contacted you to confirm the order. If the wrong price is spotted before the retailer confirms the order, they do not have to sell to you at that price.