Driving alone to the LMA will cost me:

My daily roundtrip mileage X 21 workdays/month = miles/month
X 37.5 cents / mile* = + $ for Parking would be:
(average on-site parking is approximately $250/month.
Average off-site parking is $115/month)

~•~ But, if I share the ride to the LMA, ~•~
 I will save

MBTA or Private Bus:
MBTA Bus, $31; Subway $44; Combo $71, Commuter Rail $106 - $198

My monthly fare is/would be $ + $ for parking
(at the MBTA station - $2.00 to $4.50 per day)
=   a month. 

By not driving alone I save

 
Carpool:
My total cost of driving alone is / passenger(s)
= a month. 

By not driving alone I save

 
Vanpool:
My monthly fare is/would be $ a month.

By not driving alone I save