If I joined the Marine Corps, would my utilities, food, and room and board be taken out of my pay?

The research I have done says that if I joined the Marine Corps as an office after four years in an ROTC program, that I would get about $2,000 a month as pay, and that that would be my total profit per month. But, my mother says that if I was in the military, that everything from my bed to my food would be taken out of that $2,000, and I would end up with only about $1,000 per month. Also as a side though, I heard you dont have to pay tax's while in the military, is that true?