said by FFH5:And bill-by-byte is the best method to do that.
except they don't really want to do that. that want to charge what they are charging now and add overages. That's not bill-by-byte. Bill-by-byte would mean someone that uses only 20 GB a month wouldn't be charged $50 like someone that used 200 GB. They'd only be charge $10 a month or something like that, but ISP certainly aren't going to do that because they would LOSE money.
Even a quasi bill-by-byte system should be more like $25 a month for service with say a 50 GB cap and $1 per 10 GB overage. But once again ISPs won't do that since most of their customers use less than 50 GB a month