In my experience a good portion of ROTC cadets have bought a $500 pair of Advanced Sierra-Tango Tactical Extreme Operator-Zulu Hard-Charger SEAL-certified Bada**-Industries boots. They haven't really been looked down upon by our enlisted cadre for buying them except for being the brunt of jokes involving poor budgeting. I have a pair of mid-grade Bates boots that are an upgrade in comfort and quality from the issue boots but didn't cost a car payment either. Just don't be excessive and you'll be fine, and even if you are, I don't think you'll lose any friends over it. But, my experience is only with ROTC, and not with the real Army, so I don't have a lot of experience with the very junior enlisted.