Speaking as a military dependent, if you CAN get someone to get this for you, don't flaunt it, because the person WOULD be breaking regulations and, not that I think they'd throw you in jail, since people do this all the time at Exchanges...but it's just widely regarded that you don't buy stuff for non-qualified people at NEXs, MCCXs, or BX/PXs (I don't think it's a law, just a very strong 'no-no'). I'm not discouraging anybody, but you (and more importantly, the person you get to buy it for you) can get in trouble in the very very minute chance you get caught.
It's usually not worth it though unless it's a high-ticket item...like a TV/Stereo/Appliance. That's what the rule is in place for - since if Circuit City is charging 1999.99 and the Exchange is charging 1999.99, the exchange is cheaper because you don't pay sales tax regardless of where you live, domestically or internationally.