Sytist (my old cart) had the ability to set a price list change to happen on a certain date in future at the gallery level. This was very useful for promotions where the better price goes away. There are reasons why you'd want to do it this way (maybe certain items - or a whole class of items - will no longer be available after the change) rather than using a sale or promo. I'm making a "sale" price list that I will inflate by 20% via replacement price list rather than use a promo code to do the sale so that people don't forget to use the code and email about it.