How can military personnel afford to have an apartment or house?

i was looking at the 2011 pay grade for military personnel. i realized that people that just got in 4yrs or less don't make enough to live on their own. so how do people in the military who are in active duty, but not in combat, make a living? How do NCO's and lower ranking CO's who work behind desks make enough for house, gas, food, and other expenses?