Check how sturdy they trailer is...decent prices maybe, but you might be better off checking at Northern or somewhere that deals in a little better trailer.
I bought one from Harbor Freight for my stand up jet ski, but wouldn't get one there for a bike trailer.
Small boat trailers make excellent bike trailers...most have good sturdy suspension and if you cut the tougue down make a good length trailer to haul you ride on~!~
Can usually find a real good used one sitting around for $300 and mod it the same way you would with a new one.