Find and Apple reseller like MacZone, MacWarehouse, MacMall, MacConnection, JR Music World, B&H PhotoVideo, that is NOT based in New Jersey and they won't charge you sales tax. If the sales tax savings buying from an out-of-state Apple reseller is greater than your student discount buying from an Apple Store, then go for it.
Note that you'll get a little better deal buying from an online reseller - they usually throw in some value-added deal, like some free RAM, free software, free case, free printer, etc etc. Each store is different.