Military pay is pretty complicated, and housing isn't "free". It's more like part of the compensation package. When you live in the barracks, you don't get BAH, and most singles aren't allowed to live in town unless they are E5 and win a petition to the command. Otherwise, if they choose to not live there, they pay for it out of their base pay.
All that not to argue with the financial stupid in the military, but nothing is "free", just factored into lower base pay. The biggest bane fit really is how much can be tax sheltered. My husband is an E6, and his command can't seem to fathom he has no desire to push for E7 before retirement (which means extra unpaid hours and other things to "stand out" - he cares more about family time, which I appreciate! His duty hours are painful enough as is).
They also keep harping on what he's going to do after retirement, which is in five years for us. We have been smart and have a plan that he won't need to do anything more than part time work between our savings and retirement pay. The concept of planning like this seems beyond their capacity to understand. It's crazy to that the military is one of the few remaining places you can make a good living with no degree, but so many people piss the advantage away.