For what it's worth, Dave Smith was identical in pricing to the dollar for 3 of my 4 local dealers.
As for MPG - between 11 and 14 (once, 13.5 a couple of times) around town/highway driving when not towing. When towing between 8.6 and 11 (once).
Truck: 2012 Crew Cab Long Bed 4.10 gears (usually weighing about 9,000 pounds with us in it)
Camper: 42' long and right about 14,000 pounds; 2,300-2,500 in pin weight
All of my MPG numbers are hand calculated for every tank (there's an app for that).