In article ,
says...

I do wonder how hard it would be for space X to build a falcon
equivalent of SLS orion? with at least first stage be fly and reuse?

That would be their next generation launch vehicle (LOX/methane) and
crewed vehicle (Mars Colonial Transport or MCT). No idea how much money
or time will be required. But, Musk thinks long term, so everything
being done with Falcon and Dragon are steps along the path to Mars.

Most importantly, making money in space means money to invest in the
future, just like he's done with Tesla. How else to fund and find
investors for the biggest rechargeable battery factory in the world
(Gigafactory)?

I wonder how much of the billion bucks a launch for SLS could be saved??

Doesn't matter. Congress doesn't care about saving money. In fact,
they really only care about *spending* money in certain districts.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer