When you dolly tow essentially all you have to buy is the dolly. With flat towing you have to purchase a tow bar, baseplate that attaches to your vehicle, wiring for the towed (toad) vehicle, and a braking system.
Like Jamie said, look in your manual to see if your vehicle can be towed, most automatics and some manual transmission vehicles can't. For a dolly a front wheel drive is preferred since the drive wheels are off the ground.
You also need to take in to account the weight of the vehicle you want to tow, make sure you aren't exceeding your GVRW.
Depending on where you are going, how often, and what your plans are when you get there, a rental vehicle may be a good option for you.
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