I'd advise that you wait until after graduation. I mean you are going to have less than a month to ride if you get a bike today, then be gone to basic and tech school. Then turn around and buy a better bike? I'd advise patience, or if you really want to ride right now, go hit a Goodwill store or something. Even at $150, you're going to feel invested in a bike, but at $25, you won't be, and you can still ride. If you can set aside even 1/4 of your pay during basic and tech school (I had a new car when I went in, so it was kind of tough for me) then you can walk into a shop at your first base and pay cash for a nice bike. Buy a lock too, unless you are in one of the new quad barracks that you could bring your bike indoors. Most base barracks have racks, but bikes do get stolen.

oh...and good luck in basic...it's gonna be hot. We spent 6 years in San Antonio, and summers are brutal. Not as brutal as August in Saudi Arabia, but still hot.