dont forget that it was NASA that put the ISS up - using the Space Shuttle.
In general, they like to over think their plans, and try for the Rolls-Royce solution...
cf: manned mars exploration by NASA, and Rick Zubrin's Mars Direct plan:
compare 400 Billion USD to 35 Billion USD...
oh - the ISS is about 500km above the Earth, and in an orbit inclined about 50 degrees to the equatorial plane.
-edited to correct the finances ... still not sure of the costs estimated by NASA in Bush Snr's presidency, but it was sufficiently large for congress to balk !!