To do this task
Go to the Customers menu and click Change Item Prices.
Choose the Item
Type of the item requiring a price adjustment.
In the column,
click the items for which you want to adjust the price; or, click Select All to select all the items.
In the Adjust Price area, enter a number (do not
enter a percent sign).
Select Current Sales Price or select
Unit Cost to choose the
base price to which the amount will be added.
Where are prices updated?
Changing prices by a percentage