GNC carries crap like 6-OXO and "Estro Suppress", but if you are doing a cycle, those are not gonna be very effective at all. you might as well just spend that money on a nice bra...
if you could get your hands on some gear, you should be able to get your hands on some "real" anti-estrogens, like
nolvadex, arimidex, and femara. (GNC does not carry them because they are prescription pills)