Take all the content available to a cable subscriber, and the money that goes into producing that content. Take out the ads and split the bill (in addition to the relatively low costs of operating/maintaining the cable company itself) among the subscribers. That's just covering costs; now add a bit of profit to motivate those companies to stay in business.
There's no question you'd be paying more - a lot more. We just don't think the ads are saving us money because we don't know any different - that's just the way TV has been since the beginning.