I recently bought a 1 Kg tub of it from supplement direct (totally awesome local company BTW) for 25 dollars. It is the pure stuff. I found that for me, it takes about three scoops (15g) in some juice after a workout. My muscles don't feel nearly as sore after taking it. I could work the same parts the next day no problem. I think that most people don't take enough to feel a difference.
I dunno, maybe lack of muscle soreness has nothing to do with results.
I haven't noticed any loss or gain of definition though. But, I am an out of shape atrophied mess, so don't take me too seriously.
Paulo