Honestly (and not trying to sound like a know-it-all), I wouldn't think about supplements right now. You've only been in the gym for six months...there is plenty to learn out there.
What I would recommend for a beginner is to research how to eat properly (6-8 meals a day, clean food, when to eat certain foods at which times of the day, and macronutrient manipulation), lift properly (form and different kinds of programs), and how to sleep enough (this is usually the hardest).
IF you are going to use supplements, get yourself some whey protein and/or casein protein (or a blended protein...find out when it is beneficial to use the different protein types), a multi-vitamin (NOW Adam, Controlled Labs Orange Triad, Optimum Nutrition Opti-Men, etc.), some creatine monohydrate, and maybe a pre-workout stimulant (if you find yourself needing a kick before the gym).
(JW has a mild steroid in it too...fyi)