I pull my race car on a trailer I bought new from
~Econotrailer~ in PA.
I'm very happy with it and it would be hard for me to build one myself for what they cost
The price for these is $1600 with two wheel brakes. Mine was $100 more (two years ago) because I got 4-wheel brakes.
This is a true car trailer with dual axles, LED lights, wheel brakes and a proper 2-5/8" ball coupler.
I do see folks using simpler trailers, but dual axles and brakes are *required* if you're going to carry a car in most of the states in my area and I'm pretty sure that's true in most parts of the US.
My tow vehicle is a 3.9L Ford Freestar minivan. Works great and gets 17 to 20 mpg towing. I've towed all over the eastern US with this combo and am very happy with it. I run the trans in "3rd" (non-overdrive) and rarely tow faster than 65 mph. Some of my pals have the big, enclosed trailers. These things are neat, but they really require a much bigger tow vehicle (and my mini-van is a better "all purpose" vehicle than a V-10 Dually).
You can flat tow pretty far if you pull the driveshaft, but the trailer is a better idea if you intend to tow on a regular basis.
I looked at Tow-Dollies, but they're almost as expensive as my trailer.