Allow the sale of items with insufficient on-hand quantities [System-wide]If you want to allow the sale of items that you don’t have enough of (that is, the sale would result in an item quantity and item total value of less than zero), select this option.
If you want to enter a standard cost in your item records and use that price when entering orders and bills, select this option. If you don’t select this option, the last purchase price of the item will automatically be used when you create an order or bill.