I bought and assembled a folding 4x8' flatbed trailer (Harbor Freight item # 90154), to move to Tucson. The trailer cost about the same as a one-way trailer rental would have cost. I bought a spare tire mounted on its own wheel.
I added 2x4 stake sides. To these I attached panels hacked together from shelves from plastic shelf units I'd bought at Home Depot. I used rope and many zip-ties to construct the panels from the shelves.
I loaded and towed the trailer to Tucson. I had one blowout, probably due to the wheel overheating at high speed. Small wheels rotate quicker and heat up more. For other than local use one should buy the version of the trailer that has larger wheels.
I added hinges and a ramp to the trailer. Using the ramp, an upright dolly (hand truck) and ratcheting straps, I've been able to move fridges, washers, dryers, chests of drawers, and other bulky items without incident.
I backed into a curb and bent the "feet" to which casters are attached and which, when the trailer is not folded up, hang behind the wheels. This would prevent me from folding the trailer and standing it upright. I plan either to make new "feet"or to bend them back and "sister" metal strips alongside them to reinforce them.