Bodybuilding is about caloric intake, and macronutrient intake, as long as it surpasses, or equals WHAT you NEED to get what you need DONE, (i.e, if you wish to cut, 500 under maintainence, wish to bulk? 500 over maintainence.) Meaning if you're 160 pounds, looking to put on muscle, size, weight, then bulk, meaning you'd eat approximatley 3200-3300 calories per day, 180-240g protein, 300-400g carbs (Low GI complex carbs, except post workout, then obtain simple carbs, to spare as much muscle as possible, gets stored as glucose fast, then fueled, etc.) and around 60-70g fats (More clean fats, omega-3) Just make sure the carbs, and fats are eaten at the times they are needed to (carbs being complex (Like I mentioned earlier), or if they get stored as glucose, and don't get fuled they form with 3 fatty-acid to create bodyfat)
As far as buying a protein shake, it should only be consumed once a day (post workout) and is perfectly fine first thing in the morning if you please (Because your body was in a catabolic state all night, so meal 1 needs to be a very large meal) But I recommend if you're bulking, and take one in the mornning, make a homeade gainer out of it, because it can be quite difficult achieveing over 3300 calories in pure good foods. So possibly 2 scoop whey (or whatever equals 40-50g in a serving) 1 cup orange juice (more of a simple carb, but like I said, you've been catabolic, you need it) 1 cup fat free milk (1-2% will do, don't worry too much about sat. fats, if the amount is moderate 10-12g per day, it wont' do much if any damage, and it increases testosterone levels a little) 1/2 cup of corn starch, 2 tablespoons canola oil, and BLEND. Should be around 1000-1100 calories, but don't have that alone, have oatmeal with it
Now as for post workout shake, don't make a gainer from it, it's fine how it is in the container! Get 40-50g of protein out of it, and eat around 50-60g simple carbs post workout (Bananas, sugar, etc.) Then eat another meal 1 hour after the consumption of that postworkout meal.
As far as which whey you should buy....It needs to be clean, it doesn't have to be a big brand like half the idiots in the world will tell you. Such as Musclemilk, which is highly overated, and NOT clean. Syntha-6 is fine....If you want to pay 30-50 dollars, or even more depending on where you live, every 2 weeks. Or you could go with the easiest choice, walmart whey. Which is ironicly more clean then musclemilk, contains more protein, less simple carbs (I know I said simple carbs post workout, but I perfer getting them from whole foods, and table sugar.) and A LOT less fats (MM's fats aren't good fats either) and did I mention it's like 30$ less then MM, and around 20$ less then Syntha-6? It's only 15-20$... You have plenty of more choices too... But if you can afford Syntha-6 constantly, then I say go for it, it isn't a bad choice.
Natural teen bodybuilder, OCB/INBF competitor, future student for a PHD in Nutritional sciences. Goodluck my friend!