Is this realistic?

It's not a far-fetched idea, but I don't think you can do it for 2 reasons: If you are self-employed you have to obtain a federal tax ID # and the vending machine company will require it. At 16 you can't obtain one yet. Also, I think most apartment buildings are not zoned for vending machines, so most landlords won't be able to put them in. You would make more money if you put it in work or school buildings than in residential anyway.