AZ had to offer the vaccine at cost because they didn't develop it themselves. It was a condition of the license from Oxford University.
https://www.pbs.org/newshour/health/what-covid-vaccine-side-...
I had a really bad reaction to the second shot of Moderna and I was rather pissed about it until I realized that the symptoms were almost exactly the same as those of my father who actually had Covid. Except he had it twice as bad.
So the take-away for me was that if you have a bad reaction to a vaccine, consider yourself lucky, because it would’ve been much worse if you were to contract the actual virus.