the easiest way (in my opinion) is the sum the values in column A, then sum the values in column C then take the difference.
Add a footer row to your table by selecting the table then click the add footer button in the tool bar (top right):
In the footer add the formulas as follows:
if you want a more binary answer in D10 you could also enter:
D10=IF((C10-A10) >0, "You saved money", "You did not save any money")
wayne, I think the OP was asking for a count of how often it has happend that A and C were equal. Couldnt we do that by adding an equation in D that simple read =A2=C2. Then in your footer, add a =countif(D:D, True)? That would give an actual count of number of times they were equal.
Exactly how I read it.