In terms of NASA's budget [never mind the US Federal budget] the Washington Post is ranting about rounding error only because the project is in a state for which their audience has little sympathy. Producing four fewer F35's would save more money, just on initial cost...never mind that the costs of operating just one well exceed $700k a year.
For anyone with a passing interest in the integrity of journalism, the J-2x rocket engine for which the A-3 Test Stand was built to test was let on a $1.2 billion dollar contract to Pratt & Whittney RocketDyne. The program was only killed this year [1]...and a new $2.8 billion dollar contract to develop the alternative was let just this July to Boeing. Purportedly this contract was a continuation of an undefined contract with Boeing let back in 2007 -- the same year as the A-3 Test Platform broke ground.[2]
What NASA got for the money is an additional capability that is reasonably likely to be useful over the next several decades so long as manned missions beyond LEO remain within the agency's potential mandate. Given the speed with which the hot air of politicians changes directions, moving forward on infrastructure makes sense.
[1] http://en.wikipedia.org/wiki/J-2X
[2] http://spacenews.com/41139nasa-boeing-finalize-28b-sls-core-...