Looking for a way to calculate your gasoline usage?  Look no further, download my free Excel spreadsheet calculator.  If you don't have Microsoft Excel this calculator also works with OpenOffice which is a free office suite similar to Microsoft Office. My daily commute to work is 100 miles round trip, and I always set aside the amount of money I need for gasoline at each payday.  For example, one of my pay days is the last day of the month. … Read the rest