If you're just owning a house in this resort, you can't take it upon yourself to provide wi-fi for the whole place. It's not that easy to do as well - any one wi-fi router to your house will only cover the area around your house anyway. You would need a chain of routers to cover the entire area - no one will be particularly interested in this service if they have to be on your lawn the entire time, and you'd probably tire of that too.

Just add it to the nightly rate as an "internet fee". They'll never know they could have received it for free if they didn't pay. That's what I'd do. For all they know, you have some remote turn-on system that only happened because they paid for it.

I want to get an internet connection with wifi at our vacation home at a resort. I'd like to charge other resort guests $7 per day or whatever for wifi, like a lot of places do. I'm looking for a service that will handle the whole DNS and payment processing part of this and just split the proceeds and send me a check. Are there online services that have this business model or something similar?

I know paid wifi is annoying, but it's better than no wifi, which is what we have now at that resort. If I get enough money to afford it I can solve the problem for everyone.