I wouldn’t doubt those 4 main SLS single use engines costing $500 million for the first stage alone, that’s not including the rest of the first stage costs. SLS sounds like a pretty expensive way to get to orbit. IIRC, the launch site itself cost over 3 billion.
https://www.youtube.com/watch?v=KSrFUgKCxOw
Good analysis...
Space Exploration Technologies Corp, or SpaceX, has been breaking down barriers in satellite launches, broadband LOE communications, and orbital freighters, defying skeptics. And now SpaceX is about to break the very last barrier—manned spaceflight. NASA has certified the Demo-2 Dragon 2 crew capsule for manned flight to the International Space Station. The tentative first launch has been scheduled for May 27th, 2020. Boeing’s Starliner is at least another year away from certification. How did Boeing, with all its advantages in political patronage, corporate size, experience in space, and money fall behind Musk’s scrappy startup? We take a look at why NASA has to reinvent manned space travel, the structural difference between SpaceX and Boeing, and the funding in the Commercial Crew Development contract itself.