Various embodiments determine a sale price of an item via a smart price tag associated with the item. In one embodiment, the smart price tag is detected as being shaken. Responsive to detecting the smart price tag as being shaken, a request for a current sale price of the item for sale is sent to a back end price server. The current sale price of the item for sale is received from the back end price server and displayed for a predetermined period of time. The current sale price may be displayed on the smart price tag or a separate display sign. The current price is displayed until expiration of a predetermined period of time unless a lock request is detected which locks the price of the item for sale at the current sale price. If a price unlock button is pressed, the sale price of the item is unlocked.