Target has a lot of their building sets on clearance for 50% off. This is a great and rare discount on these toys. Here are some of the sets available although, you can see them all here.
Lego Prince of Persia Set – The Ostrich Race 7570 $9.98
Lego Racers Jagged Jaws Reef 8897 $10.48
LEGO Atlantis Deep Sea Raider 7984 $14.98
LEGO Toy Story 3 Pizza Planet Delivery $14.84
Atlantis Gateway of the Squid 8061 $14.44
Kre-O Transformers Sentinel Prime $19.98
Some of these ship free with a $50 purchase. For others you will need to pay shipping or you can always get free shipping and an additional 5% off if you have a Target Red Card. Een with the shipping charge this is a great discount on these sets.