For me, the trailer would be $1100. The 'golf' wheels and tires I looked at sitting in the back of my pickup were a good chunk of change but, that doesn't include axles or construction costs.
Putting Golf Cart wheels on a non-patio model smoker is not as easy or cheap as it will be on most patio smokers. Whether it costs you more or less depends on where you live, who does the work and, where you source the parts and pieces. Plus a trailer will be rated for 'road use' where a Golf Cart wheel option will still require a trailer to hit the road.
I have personally seen smoker trailer options for a 250-gallon smoker as much as the smoker itself from some vendors and others that are a lot more attractive. There are a huge number of variables and unknowns in trailers so, comparing one price to another is not an easy or obvious task.
YMMV :wink: