The problem is that the ISPs' approach has little to do with passing their costs on, and more to do with holding back new forms of media distribution. Price/GB should be nonincreasing, with a nonnegative connection cost. I've seen pricing plans with $50 for 250GB, but $1.50/GB overage. Clearly, the fixed cost is not -$100, but is intended to punish heavy users rather than selling them what they want.