Earlier quoted context omitted.
It was a horrible failure. It was projected for 75 launches a year at about 25M$ (thats million dollars, not a software company in Seattle) per lauch from 1977 until the late eighties when it was scheduled to be replaced by something better. Instead it was 135 launches in 30 years at 1.6G$ per lauch, and it totally crippled NASA's capabilities to develop a replacement.
you may want to change G to B. In the United States, where dollars are used, G is more likely to mean "Grand", or 1k. B would be billion. Or, when all else fails, just type it out.
Things like kUSD or M$ appear to have come from science - it's putting an SI prefix to a unit. Personally, when I write M$, I mean one megadollar, not 1 milion dollars.