The initial value for Price is given by initial price but there is no arrow from initial price into Price. When you open the Equation editor on Price you will not see initial price listed as in input.
| Ø | Click on the Variables button |
| Ø | Select initial price from the list presented and click on OK. |
| Ø | Enter the Units as $/Box. |
| Ø | Click on OK to close the Equation editor. |
Another way to find variables to insert is to change the selection from "Causes" to "All". At that point, just click once on the variable that is needed.
Note that if you had drawn an arrow from initial price into Price then initial price would have appeared on the input list. However, when you close the Equation editor the arrow will disappear because initial causes are not, by default, shown on model diagrams. If you want to keep the initial arrow select the menu item Model>Settings, click on the check the Sketch Appearance tab and check Show initial causes on model diagrams.
