Using the setting Allow PO Pad cost price to change you can allow users when placing an order through PO Pad to override the list price that is currently set, the purpose of this setting is to allow orders to be placed at the current price of the product such as daily specials.
Click the Admin Cogs along the top bar.
Click Mini Markets, then Manage Mini Markets.
Edit the mini market and stay on the Details tab.
Open the section Order Placing by clicking on the words order placing.
Locate the setting Allow PO Pad cost price change and use the check box to activate or deactivate.
Scroll down to the bottom and click Update to save any changes.