The hullivator gets the job done well, but its pricey. A low cost option is the Reese Canoe/kayak loader. You need a hitch receiver to use one, but it works and it is inexpensive. I use it on my 4th gen to load my Hobie Compass onto the roof. I use a trailer for local fishing, but if I go out of state, I use the roof loader and leave the trailer home. I recently used the loader to transport some 10ft planks home from the lumber yard.
I paid half the price for my Reese Kayak loader from Amazon when I bought it a year ago. It is now priced around $55 but still pretty cheap alternative.
Amazon.com: Reese Towpower 7018100 Canoe Loader - Black: Automotive