In my view, a 200 buck used single axle boat trailer with small wheels and tires (12" rims is what they usually have), is ideal especially for the p;rice plus it already has a tongue.
In fact I leave my TC on the trailer all winter, I just run the jack legs down 'till they touch the floor and call it good.
Old boat trailers are pretty easy to come by. Craig's List is full of them.
As a side note, I've always been suspect of Harbor Freight products. Their Predator engines aren't bad (they are actually Lifan) but the rest of their stuff is questionable.