Hia,
I know a fait bit about nutrition and such, family members have been in the trader for eons. myprotein.co.uk is your best source for good value for money, also...protein powders are only effective if used with a stable week in-week out approach to eating at least 5 protein full meals a day. To put mega size on, you need to change your training anyway, serious weight with few reps to failure is the way
You'll not notice uber gains simply from using supplements, as that's all they are, an addition to real food.
Make sure to find out what protein intake you need each day and back it up with amino acids and proper creatine that you take with a glucose based drink thats tailored for creatine. Plenty online about it.