I saw this thread get bumped toward the top so I thought I would see what the opinions were on it. I looked into this idea many years ago and determined it was not a money maker.
What I found comical about this thread is it was the last post the OP ever made. Not one single question answered. Did one of his vending machines fall on him later that day?
It has probably been 10 or more years since I looked into it, but I recall routes for sale every week in the Sunday paper. If they were such a big money maker, there wouldn't be so many people trying to unload them.
You definitely need to compensate the property owner. Would you allow someone to make money from your property without something in return? You also have to establish a system to pay refunds for when people lose money. If it is not well posted, you can be sure that your machine will take a few kicks are a punch or two. One costly repair could wipe out any profit you have.