I think to look at any particular war and ask that question leads to an inaccurate answer... since there are years of prep work, training, research, etc that the military conducts, then in a short period of time they expend equipment, munitions, etc during a war.

But consider, the cost of labor effects everything the military does... Everyone in the entire chain commands a higher wage than they would in China/Russia, whether they hold a gun or not... researchers, assembly line workers, doctors, etc... pushing up the costs of everything the military buys.