The operator is 'sumif', which means add the number only if an indicator is set.

To do this, you need a way to tell Excel to add the number *only if Wal-Mart is the store.

1. Set an indicator for Wal-mart. Possibly something like add numbers if column g = w. the formula looks like this:

a1+SUMIF(c1,"w",b1)

=a1 (the Wal-mart total)
b1 the column containing the amount paid for this transaction
c1=the indicator. If not 'w', the sum will not happen.
The answer will appear in the column where the formula is.

Good luck!

Add column B to column a only if column C = w