Yeah, it could be $8K per kilo!
If you go all the way to the end, though, beyond geosync, and let go, the slingshot effect is pretty strong. Out at the end, a hundred kilo package to Mars or the Moon becomes much cheaper than a launch from Earth surface.
A beanstalk on the Moon, now....
The Greenies would never allow such a thing. If you run a mass out 30,000 miles and let it go, you steal from Earth’s rotational energy, and don’t get it back unless you attach an equal mass of, say, refined asteroidal heavy metals (iridium, platinum) and wind it back down to the surface.
Robbing Mother Gaia of her precious angular momentum!
Enough of that and it’s the End Of Days!!!!