@jbkdistributors- 

"My vendor bills look like this:

500 Boxes @ 24.95

200 Boxes @ 22.95

350 Boxes @ 28.00"

The way to enter the formula for 500 boxes @ 24.95 is 500*24.95 <tab>.  The asterisk is the multiplication sign just like Excel.  You will get "The value is out of range" error message when you press the asterisk key but keep going and enter the full formula.  Watch this video if you need further guidance: