Terrible idea. That means that it will be harder to judge what your Internet will cost you.
Where I live, almost no one has that kind of variable price for electricity. The only one that does is big electricity users like companies. Almost all private persons has a fixed price for the electricity per kWh, like 0,4$â/kWh. I think that proves that most people don't like that kind of variable billing - they actually pay a bit more to avoid it.