Online is cheapest. Bulk Nutrition is the only one I go to. You may also want to try buying from the factories that make the protein such as protein factory, true protein, ect. You can make your own blend and it's usually about $6 per pound. CEE is a new type of creatine that doesn't need an additional transport module for it to be effective. On stands for Optimum Nutrition. Nlarge is a weightgainer shake that I found to be very cost effective with quality ingredients. Your best bet is to check out these online sites below. They have a description of what each protein does and recommends what you should buy depending on what you're after. Go to the protein factory. It's one of the best for descriptions of what you should take.
www.trueprotein.com
www.proteinfactory.com