"k" is slang for "kilometers" or "thousand".
for example:
How fast was he going? 100k or 100 klicks
How much money does he make? 50k
M = million or mega, for example, a top hockey player can make 10M/yr.
G or B = giga or billion, for example, the U.S. defense budget is 300B.
T = tera, for example, I have a terabyte drive.
