The Field Crew Preferences screen can be accessed from your Method dashboard by clicking the vertical ellipsis [] on your Field Crew app and selecting Preferences.
This will take you to the General Preferences for the Field Crew app.
Show Prices: When enabled, the Field Crew app will show the cost of each item added to the work order.
By default, prices are shown in the Work Orders app:
When disabled, the prices are not shown: