Why stop at the ISP level? Have a system that allows the user device to negotiate a connection with whatever services are available. The service could offer bids from providers which would have to specify a service level and price point. Then have a second price auction for every unit of time (say 10 mins). The user tunes their device to get the level of service and price they want. A contract would then consist of a VPN provider who would make bids on your behalf for a fixed monthly price.