I found a number of sets on 50% clearance, including Atlantis, Ninjago, Pharaoh's Quest, Kingdoms, Toy Story, Cars, and Star Wars.
Some highlights include:
Mill Village Raid
Star Wars Advent Calendar
Mace Windu's Jedi Starfighter
Plo Koon's Starfighter
Emperor Palpatine's Shuttle
Hoth Rebel Battle Pack (though there was only one in the store)
Target had a lot at 30% off as well, but nothing compared to Walmart.