The Costco ad has just been posted. The Galaxy Tab 2 10.1 will be $100 off and the Galaxy Tab 2 7.0 will be $70 off. Not sure what the base prices will be before the discounts.
Samsung recently dropped the price of the 10.1 from $400 to $350 and the 7.0 from $250 to $200. Before the price drop, Costco was selling them for $380 and $240 respectively (and lower with instant rebates). I haven't checked Costco's prices since the price drop.