I think the only reason that they do that is because the item is out of stock and they need to get more in and don't want people to buy it till stock arrives, or they are away on holidays and dont want people to make a purchase as they are away and can not ship it and dont want to deal with the demanding 'where is my part, i paid for it a week ago' type of stuff.
If you click on the qty sold you will see the ones that have sold have been at normal prices.
