Just for something to do, or thinking as a cheap way to build a trailer? What are you wanting to tow on it?
Probably cost the same as a normal trailer, but look a lot worse. Just my cynical opinion though. My trailer cost like $900 and has jockey wheel, spare wheel, the works. By the time you fart around, i'm not sure how much you'd potentially save. Axle position will be bad and it will look weird. Resale on trailers is good too, "kustom" ones, not so much.