I tried to go for that one too, lol. But, you obviously got there before me. x)
It's a great name in that everyone knows and recognizes the term "Free WiFi", but the issue is: "free" isn't exactly sexy. So, it's hard to sell/monetize (IMO).
My idea, and probably everyone else's too, was to create a map of free wifi spots. Create site/app and monetize with ads.
Something else you might be able to do is: supply public spaces and businesses with Free Wifi (for free to the business), and then find a way to monetize the users (with ads?). But, this would be a lot more capital and time intensive.
I'm not sure what else to say. It's a fairly limited domain, and hard to put a numeric value on...
Good luck!