I have a 2500 HD Gas. I thinking abouting getting a diesel. With my truck now I am getting about 10 mpg pulling and about 13 miles in the city limits. I pay approximately $100.00 to fuel the truck....
Depends upon what you tow and how much you tow..to figure if it makes sense.
For caparison, I tow a 31 footer, loaded weighing +-9000K. I get pretty much 12mpg towing and about 15 mixed driving empty..maybe more on a long cruise control run.