I guess it depends on what you want to tow or how much you want to install yourself. I got the tow package with the truck since it came with a class IV hitch, oil cooler, brake controller harness, bigger battery, and bigger alternator without me installing a damn thing!
If you're planning on towing 3500lbs or less, any class III hitch and wire harness will do. If you want to tow up to the 6500lb capacity of the truck you'll need a class IV, oil cooler, and tranny cooler if it's an auto. Bigger battery and alt might help too if you want a trailer with electric brakes, lights, battery, etc.
I don't know if a dealer will install all the parts for the tow package for you or not, or how much it costs. Was that price for the hitch alone?