One idea:
If all you want is those 3 options, you could use a data validation list.
Select the cell(s), and go to Data\Validation. On the Settings tab, select "List." Then in the box, enter: 0,$,? (you do not need quotes around them).
Press OK, and you should have a list in the selected cell(s) containing those 3 items.
If you want it to have a red question mark, you could use conditional formatting. With the cells still selected, go to Format|Conditional Formatting and use
Cell value is | equal to | ="?"
Click the Format button, and set the font color for this condition to red. Click OK until you are out of all of the dialogs.
Now you should have a list in the cell, and when you select the question mark option, it should turn red.