While using a truck bed is a quick and potentially convenient option for transporting a single ATV, you are going to first need to buy a truck. If you happen to have a truck and only need to transport a small ATV (under 55 inches), you may have found your solution right there! If you do not want to spend $50,000 on a way to transport your ATV, a trailer may be a better option.
Trailers offer several advantages for heavier loads or multiple vehicles, and they don't require extra purchases. Trailers also provide more space so that multiple ATVs can be transported simultaneously without risking damage to each other. Instead of having to purchase a ramp for your truck, you can simply pull down the ramp on your trailer, which is already there (often it becomes the rear wall).