Its not that high, because its designed from the beginning to be produced in the 100s per year. Its probably being produced faster almost every other rocket engine (outside of SpaceX own) and maybe some much simpler engines from Russia or China.
They are producing SN100ish by now. A while ago they said 2 million $, already cheap for such an engine. Target is more like 200k$.
So likely its between 1-2M. That would make it only about 6M per flight based on the engine.
Even more amazing when you consider a full flow combustion rocket engine is an engineering masterpiece. The design and materials science are priceless.
Compared to what NASA is paying for the SLS engines (over $140 million each), it’s loose change.