Grocery King allows you to represent % of item used which can be useful to quickly gauge whether item needs to be purchased before it runs out. You can easily adjust % of item used from the Edit screen. Tap on the item to open the edit screen as shown below. Now move the slider under section "Percentage of stock remaining" left or right to decrease or increase the % of stock. As you can notice when you reach 50% the color changes to Orange and when the slider is moved to 25% and below it turns red. This is useful on the main screen to quickly focus on items that need attention.
Percentage of item in stock can also be used for items that you purchase wholesale. For example if you purchase 24 rolls of Paper Towels and you currently have only 12 left, then you can move the slider to 50% to represent it.