Right now, I got two steals via GNC.
Dymatize Elite Gourmet (Whey and Casein), 5 lb - $25 ($20 w/Gold Card).
GNC Soy Protein 95, 4 lb $25 ($20 w/Gold Card).
And, although it's not powder, I picked up two steals from Vitamin Shoppe, RTD-style
12-pack ABB Max Recovery, $21
ANSI Ultimate Flurry Hi-Protein (40 grams), 15-oz cans - $1.23 each. I've bought about six of these, so far.