Keep in mind that getting what you pay for in this case involves transporting your camper at freeway speeds. If just one little component fails, you could lose all your investment (materials and labor) in the camper, all the stuff inside the camper, have damage to your car and possibly damage, injure or kill others on the road with you. So don’t get caught up in false economies. That HF trailer has absolutely nothing likeable about it other than the price, which will keep going up and up if you count in the required annual maintenance to keep it from being a road hazard.
All that said, do you live near a boating community? You can almost always find an ancient boat for sale cheap (or even free for hauling off) that includes the trailer. Trash the boat and rebuild the trailer into something for your camper. There’ll be lots of hacksaw work and drilling, but nothing really too difficult. Even re-packing the bearings is more messy than complicated. Just remember, don’t weld galvanized.
Good luck