Product prices can be edited temporarily on the current basket.
Tap on the product in the basket.
Basket Product Price
Tap on the price field.
The price can be increased or decreased by an 'Amount' or 'Percentage'. 'Amount' is selected by default. Type in an amount.
Type in an Amount
When you type in an amount, the original price and new increased price is displayed. If you would like to reduce the price by the same amount, select the '+/-' button on the number pad.
Tap done to apply the new price to to the product in the basket.
Modify Price by Percentage
In price edit, tap 'Percentage' to edit the price by the percentage you enter.