$14.99 is what National Car Rental is charging this weekend at DTW airport. I used that as an example that it can often be cheaper to rent a pickup from a rental car agency than to use U-Haul or Home Depot. There are often specials at other National locations as well.
You won't find any heavy-duty pickups (i.e., Dually) in the rental fleets. You are most likely to find a Dodge Ram 1500, Nissan Titan V8, Ford F-150, or Chevy Silverado.