2nd for horrible reasons.
-Buy some sneezing powder, always carry it with you.
-Whenever you get tired of your body. Find a tall building.
-Jump off it to your death, powder in hand, sniff sneeze,
-Now you can keep your new body as no one can claim it back as they just died in your old body.

Now you didn't think about that every dead body has a tiny bottle of sneezing powder on them. Someone eventually finds the link and catches you when you go buy a specific brand at the same store. You can't just carry enough and leave the bottle because there would still be traces of the powder on the bodies that they'd find during autopsies.

Perhaps instead of killing them all. You take half of each person's bank account to pay for a giant warehouse, [the other half of their money is for you to spend in their body on drugs, whores or whatever is fun in that bodies life.] where you imprison everyone you jump into.
And keep it filled with foods and such so they don't die. To open the door into the room there's a keypad only on the outside, you can just sneeze to get out. The keypad code is only known by yourself.
And you hire one person. A convict or an illegal who doesn't dare piss off their employee and get fired. That person signs for food or any deliveries. Also use some of the income from each person to pay off cops to keep them away from that warehouse. Look into hiding any heat signals from all the bodies, soundproofing the warehouse so no one can scream for help and running a legit internet company where you sale cheap chinese imports and custom dog collars. Cat sizes available too after two years of service.

Or! You could have lived your entire life, be a old man. And you sneeze for the first time[after so many swaps that you learned how to control sneezes.] And you're lying on your deathbed. And you sneeze. You are not in the body of a 3 year old boy. Who's a perfect healthy little boy. You could learn to control sneezes and live forever. One body to the next.

I hate to say this... but this option doesn't say anything about swapping bodies... just places :P Although swapping bodies might make an interesting option. :)