Welcome to the quest for the Holy Grail, in this case, the ultimate fair and profitable internet billing system.
I once suggested that one bill by session, using the telephone network switch model. Payment for local packets, that only went through one router, would be essentially free. Packets that had to go through the cloud, would be billed by the number of routers required (i.e. traceroute hops). I called it FUBAR (Fair User Billing And Routing) which wasn't very popular with my client(s).
Incidentally, such billing systems are often patented. For example, here's one that bills by routing:
I like this one. If your router gets overloaded, you simply charge the customers more. Presumably, that will inspired them to reduce the overload. Probably useful for delaying upgrades:
Here's a method that bills by session:
While intended for cell phones, it can be adapted for internet billing. Customers would be billed by "node" or server. Wanna connect to my web server? Fine, it will cost you $0.00001 per minute. Past implementations were called "micropayments" which are currently functional among some online games.
There was also a time, where some providers (i.e. Comcast) were using the Hollywood model. Movie theaters charged by the user. If you and your friends go to the movies, everyone pays. In this case, you would pay by the number of computahs. Software was scribbled to guess the number of machines hidden behind an NAT router, and telemarketers were dispatched to extort additional money from customers. Predictably, it was a PR disaster and was instantly dropped.
Currently, we're heading for what I call the Smorgasbord model. All you can eat and one rate. However, if you eat like a pig, you get thrown out.
I'll keep my ideas to myself. However, I would be interested in what others consider the ultimate fair and profitable internet billing system. There are plenty that are more fair than flat rate. There are also plenty that are more profitable than flat rate. The trick is to invent one that is both.