A cursory reading of the decision (PDF), and most reporting on it do suggest that it allows the president to sell pardons. Clarity that it does not can be found in a footnote, which reads in part:
JUSTICE BARRETT disagrees, arguing that in a bribery prosecution, for instance, excluding “any mention” of the official act associated with the bribe “would hamstring the prosecution.” … But of course the prosecutor may point to the public record to show the fact that the President performed the official act. And the prosecutor may admit evidence of what the President allegedly demanded, received, accepted, or agreed to receive or accept in return for being influenced in the performance of the act… What the prosecutor may not do,however, is admit testimony or private records of the President or his advisers probing the official act itself.
Who’s going to prosecute him? He can just imprison or fire anyone who tries.
This is presumably in reference to a past president, who would not have those powers. The legal issues surrounding prosecuting a sitting president have not been explored, and this ruling does not address them directly as they were not relevant to the case.
But Trump won’t be a past president because he won’t leave office until he’s dead. He’ll never be prosecuted, and he knows it.
I have a different take and I think the Chief Justice is being intentionally vague here. He references a bribery prosecution but never specifically mentions in the footnote whether he is referring to the issuance of a pardon, which is a core function, and thus entitled to absolute immunity based on the rest of the opinion. It’s also not clear whether he is referring to a prosecution of the briber or the person being bribed.
Reading Justice Barrett’s partial concurrence, which is what the footnote responds to and also included in the linked ruling addresses your concern. Justice Barrett is unambiguously talking about prosecuting the president for accepting a bribe.
The federal bribery statute forbids any public official to seek or accept a thing of value “for or because of any official act.” 18 U. S. C. §201©. The Constitution, of course, does not authorize a President to seek or accept bribes, so the Government may prosecute him if he does so.
Except a pardon is a core function within the president’s constitutional authority, not just an official act, thus based on the opinion entitled to absolute immunity. The footnote exchange is only referencing official acts (which are entitled to presumptive immunity) not core constitutional functions (like a pardon).