Budget, Ryder, Penske, are all worth checking with. Dont know if they'll be cheaper than UHaul until you get a quote from them, cuz on a 1 way transport, it depends on where you are going from and to, and how much demand they will have for the trailer where you take it...
Since its a 1 way trip, it may be worth your while to search withing a couple hundred miles of where you are to find the place to rent the trailer... If a Penske shop 100 miles away will rent you a 1 way haul for 200, you'd save a little...
Nothing wrong with the option to buy a trailer, other than the cost of ownership (title/registration/insurance) can be cost prohibitive in some states, unless you actively use it ... Maybe you could sell it when you get where you are going...
