The author sets the price. Specifically, the price the publisher -- any publisher -- pays the author to make a copy. Publishers can add a margin to this to cover distribution costs, but then they're in competition with other publishers and customers can buy from any of them.
No other contractual terms. The author only sets the price publishers pay and that price is the same for every publisher. Authors can sell directly to the public but still can't impose any additional license terms nor sell for a lower price than the one publishers pay. Individual members of the public can also make copies on their own as long as they pay the fee.
Then any publisher that wants to publish the work simply does so and pays the author the author's fee, which the author can only change once a year and only change uniformly for all publishers.
No other contractual terms. The author only sets the price publishers pay and that price is the same for every publisher. Authors can sell directly to the public but still can't impose any additional license terms nor sell for a lower price than the one publishers pay. Individual members of the public can also make copies on their own as long as they pay the fee.
Then any publisher that wants to publish the work simply does so and pays the author the author's fee, which the author can only change once a year and only change uniformly for all publishers.