Sorry about dropping this a little late in the week. I had to get the reviews out of the way first.
Target is running a BOGO40% Off sale on Friends, Star Wars, City, and Duplo sets this week. If it's like last week's sale it'll stack with Clearance prices. Also, if you get two of the same set it's effectively 20% off each.
Toys'R'Us is running a 20% off select Lego sets sale. There's a few good deals here.