Check auction sales in your area classifieds of course and local dealers usually have used trailers for sale. I found mine through horsetrailerworld.com Don't rule out stock trailers they are usually less expensive than some horse trailers. Make sure you pull the mats and check the floors of any you look at. Thats the first place they start to rot.
Sorry forgot to add that yes most do have a plain ball hitch on a bumper pull. Mine has a weight ditribution hitch but its a large bp
Make sure your vehicle can pull the weight of what you are looking at and the ball size is correct. There are some places that do rent trailers, check local trailer dealers.
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