Some apps in the Play Store are displaying original and sale costs and although this doesn't appear to be listed for every single app which has gone on sale, it's possible that Google could be testing this new way of labeling for applications and games which go on sale for a certain amount of time but are planned to boost back up to the original cost at some point. While this isn't a major change to the way apps and other content are listed in the Play Store, it could perhaps give users a better understanding of how much of a sale they're getting once the price drops on an app or game, and give them a sense of urgency to pick something up as opposed to hanging out on the fence without deciding one way or the other.
While sale prices are great, they were always just listed with the sale price, and unless someone had been considering an app or game for a while and already knew what the original cost was, users could likely assume that the sale cost was the original cost. This adjustment could help to clear up any confusion that people might have had about the matter, especially if it goes widespread and Google makes it a thing for all content.
Sale and original costs are showing up for the apps that have them listed in both the search results and the regular lists, so no matter where you find the content, if Google has it listed with the sale price in addition to the original price it will be visible anywhere the app shows up, meaning there is zero possibility to miss these details. These apps also show when the sale will be over, which leads back to the particular detail about a sense of urgency as consumers will be much more informed about the sale pricing itself and will be able to make a more informed decision on whether or not to buy. Right now it only seems to be showing up for a handful of the different LEGO games from Warner Bros. so there's no telling when or if this sort of thing will be visible from other developers.