You can enable manually setting a price for an item in the POS.
Enable Changing Price:
In the POS go to Settings -> Preferences and turn on "Show manual pricing".
Change price of a drycleaning or alteration item:
1. Add the item to an order.
2. Click "Upcharges."
3. Click "Update Price" at the top of the upcharges.
4. Set the total price. Note that when you have changed an item price manually, changing the quantity or adding upcharges will NOT affect the price.