You can make a deal with anyone distributing them. It's a matter of paying enough so the medical worker can add the sample to /lost or broken/ section. Manufacturers are very strict in their distribution of samples, so I cannot think of a way to get one without the help of someone.

However in 2023, there are many examples already of Pfizer and other samples under microscopes. You can compare them, so you can confirm that they observe the same thing. Regardless, I doubt you will find anything new if you just now want to observe a Pfizer sample... Still, in case you manage, I would be happy to view your evidence on the subject.