People that respect property rights don't have any problems with people freely negotiating prices between one and another. It happens every day.
What YOU are proposing though is much, much different. I wish I could get you to grasp this, but ignorance is a regular epidemic these days, or so I've heard.
Having the government set a price by force is wrong. If the company on the other side of the bargaining table is not free to take the deal or walk away, but is forced to agree, we don't have a free market anymore and I am against that with all of my being. All people who love the Constitution feel the same way.
People have been governing contractual terms between parties for centuries. Contractual terms have been set for centuries. Price is a contractual term and has been set by third parties for centuries. Where have you been? There is a whole rich literature regarding societies management of negotiations, property, offer and acceptance, promissory language. Go read the literature before you speak.