Not that easy. If you want to register a bitcoin ATM business you need to have a company and register them with the government. There will be a lot of procedure and a lot of cost for installation. I think you'll go bankrupt before you book your first ATM. Recently a few illegal ATMs have been dismantled in the US and France.
I guess it depends on your jurisdiction and one-way vs. two-way. Here, one-way machines are considered "vending" machines and they don't cost much in the way of legal/gov't fees to get up and running legally (although I think two-way is the better option).
"7.5%? I would never exchange a penny." - Thanks, also good to know and why we are still researching (it's been hard to get real-world user/owner feedback)... 7.5% is just a jumping in point based on being lower than any other BATM market but obviously better to know what users are really willing to pay.