1 scoop has 22 grams of good quality protein. I take 3-4 scoops after working out (i.e. lifting). So if you're working out everyday it will last you 8-10 days (there're 32 scoops in a 2 lbs container). I mix the scoops with 1% milk and use a hand-blender (it's a b**ch otherwise as the protein likes to clump).
I bought the 10 lbs, and still haven't come close to finishing it and it's been a year. But then again, I don't lift everyday (maybe 3 times a week) and if I'm going to be eating right after lifting, I don't take protein. Taking too much protein can be a nasty thing -- it won't hurt you, but you will smell like a skunk. Remember those guys in the gym that you can smell like 100 feet away -- those are the ones probably overboarding on protein. Or they don't know what deodorant is.
If you're trying to gain mass, taking twice your body weight in grams should be your upper limit. I would recommend taking 1.25 to 1.5 times your weight in grams of protein per day.
Hope this helps.
D.
P.S. No one likes Van Damme.